The world's most spectacular border ceremony takes place every day before dusk at Wagah. Roughly halfway between Lahore in Pakistan and Amritsar in India, Wagah is where the Grand Trunk Road  intersects with the so-called Radcliffe Line, dividing the Punjabi town between the two countries. The only official road link  across the highly contentious and fairly recently fought-over Indo-Pakistan border passes through the town's monumental border gate.
As large crowds gather on either side of the gate, claps and cheers of "Pakistan Zindabad!" and "Jai Hind!"  charge the air with anticipation, as if before a sports game. What follows the closing of the gate is indeed a contest between two teams. The khaki-clad ones are the Indian Border Security Forces; the Pakistan Rangers are resplendent in black. Each of the players is over six feet tall, sports fearful facial hair and carries impressive turban-cum-coxcomb headgear.
The apparent intent of the synchronized ceremony is to lower the flag of both nations before sunset. But as the sentries from either side dance their aggressive no-touch tango, the real object of the ceremony becomes clear: to act as a vent, right here on the geopolitical fault line, for the deep hostility and mutual resentment between India and Pakistan. In an unintentional side effect, the ceremony also exposes the mutual resemblance between both sides.
It's been called "carefully choreographed contempt" : the soldiers mirror each other's goose-steps, thumb-thumps, martial cries and intimidating stares. This curious hybrid of battle and ballet may last up to an hour. When both flags have been hauled down, the only physical contact between both sides occurs: a curt handshake between officials, which signals that the ceremonial border gate is officially shut.
And all this for a trickle of traffic. Apart from a few border-crossing tourists, the number of locals going back and forth is no more than a few dozen each day. Such lack of interest in each other's affairs reeks of the contempt bred by familiarity. Pakistan and India share truckloads of history, but in their relationship, that heritage counts as "baggage." The half dozen wars and skirmishes fought between this South-Asian version of Cain and Abel can all be related to the moment of their conjoined birth in 1947, when they were severed by the Radcliffe Line - a hastily drawn up border that remains an open wound, even if dressed in the colorful bandage of Wagah's daily flag-lowering ceremony.
At the end of World War II, a victorious but weakened Britain realized it could no longer hold on to India, the jewel in its imperial crown . That was due in no small part to the non-violent resistance pioneered by Mahatma Gandhi, which revolutionized revolution itself. Sadly, Gandhi's vision of a peaceful, non-communal India didn't survive the British Raj ; other leaders of the Indian independence movement pushed for territorial separation based on religion, notably Muhammad Ali Jinnah's Muslim League, which feared becoming a minority in a Hindu-majority nation.
One could argue that this split in the pro-independence camp was not only to London's tactical advantage, but also at least partly of its making. When, in the first decade of the 20th century, the Indian electoral franchise was widened to include more locals, it was partitioned along confessional lines. Perhaps out of concern not to marginalize certain groups; but perhaps also with a mind toward that age-old adage, "divide et impera" . If so, only the first part of the policy was a success. The post-war Labour government of Clement Attlee wanted to get rid of India in a hurry, the only sticking point being how not to get blamed for the intensifying communal conflict.
In early 1947, Lord Louis Mountbatten, the last British viceroy of India , set the deadline for independence for Aug. 15. On July 8, the British lawyer Sir Cyril Radcliffe arrived in Indian with a brief for a line on the map that would divide Hindu-majority lands from Muslim-majority ones in as equitable a manner as possible. Radcliffe was a brilliant legal mind, but he had no border-making experience, nor had he ever been to India - though such "impartiality" was judged to be an advantage by all parties involved.
With barely five weeks between start and finish, Radcliffe had to chair not one but two boundary commissions: one for Bengal in the east, another for the Punjab in the west . Each Radcliffe Border Commission was composed of four judges, two from the Muslim League, two from the (secular, but mainly Hindu) Congress Party. The resulting deadlock left all the major decisions to Radcliffe himself. The goal of both commissions was to establish contiguous zones containing comfortable majorities of either side's co-religionists - but Radcliffe was allowed to take vague "other factors" into account, including (but possibly not limited to) infrastructural and economic considerations.
Mountbatten instructed Radcliffe not to mind the military angle - the artificial borders would be indefensible anyway. Radcliffe followed existing subdivisions, generally but not precisely following the course of a few rivers, creating a very convoluted border indeed.
Understandably, Radcliffe's final proposals met with howls of disapproval from both sides. Even before he had completed his work, mutual suspicion and rumors about the eventual course of the border led to deadly violence on the ground. To create perceptual distance between the independence of India and Pakistan and the accompanying riots - and especially to deflect blame for the latter from Britain - Mountbatten postponed publication of the Radcliffe Border Commissions' findings to two days after Aug. 15.
For those two days, India and Pakistan were like conjoined twins. With long stretches of the border undefined on Independence Day, some towns raised both the Indian and Pakistani flags. Following the release of the border scheme, called the Radcliffe Award, violence escalated to horrendous levels. When all was over, pogroms and ethnic cleansing had left up to 1 million dead and forced 12 million to move one way or the other across the new border.
Disgusted and horrified, Radcliffe burned all his papers and refused the fee of 40,000 rupees for his work. He left on Independence Day and never returned.
His border may have been hastily and arbitrarily drawn, but it is hard to see how any new, religion-based borderline across relatively integrated lands would not have led to chaos, violence and bloodshed. Yet the speed with which Britain wanted to leave India, and the internal dynamics of Indian politics, necessitated such a border. Radcliffe's commissions achieved one goal: they gave all parties involved cover - everybody was able to blame the border, and its bloody consequences, on everyone but themselves.
The term "Radcliffe Line" is sometimes applied as a pars pro toto to the entire Indo-Pakistani border. But to be precise, we need to distinguish between the two Radcliffe Lines  drawn up by either of the Radcliffe Border Commissions: the current Indo-Bangladeshi border, and the Indo-Pakistani border as it runs through the Punjab. This second Radcliffe Line forms part of the so-called International Border, which courses down to the Arabian Sea, dividing the Pakistani provinces of Punjab and Sindh from the Indian states of Punjab, Rajasthan and Gujarat. This is the least-contested part of the line dividing both countries , running through the thinly populated Thaar Desert and the Great Rann of Kutch, an enormous seasonal salt marsh.
The tricky part of the 1,800-mile line dividing Pakistan and India lies north of Punjab. This used to be the princely state of Kashmir, the ruler of which had to decide after independence whether to accede to India or Pakistan. Because of the state's Muslim majority and its contiguity with Pakistan, this should have been a no-brainer. The state's Hindu ruler had other plans. But while the maharajah was maneuvering to keep Kashmir neutral and independent from both - a sort of Himalayan Switzerland - a pro-Pakistan rebellion forced him to ask for Indian assistance, which was granted only after Kashmir agreed to join India. War broke out between Pakistan and India, and the two newborn countries fought to a standstill over Kashmir in 1948, and again in 1965 - and again in 1999.
Most of Kashmir is Indian-held, while the Pakistani hold a crescent-shaped eastern bit. The line dividing both is not an international border, determined by a commission, a reassuringly full line on the map, but a "line of control," the result of an armistice, represented cartographically by the much more ephemeral dotted line.
To further complicate matters, there's also a "line of actual control" in the subcontinent's High North, dividing territory held by India but claimed by Pakistan from territory held by China but claimed by India (got that?). This area, called Aksai Chin, was occupied by China during the brief Sino-Indian War of 1962 . And while India and Pakistan agreed to respect the line of control by the Simla Agreement in 1972, that document left out the Siachen Glacier, subsequently occupied by India in 1984 and occasionally skirmished over (although sub-zero temperatures and avalanches claim more lives than the actual fighting).
Radcliffe's arbitration, and the subsequent subdivision of the subcontinent, has had many unintended consequences, the most important being the elevation of the British Raj's intercommunal conflict to that of an international fault line. A chilling addition to the ever-looming risk of war occurred in May 1998, when first India, then Pakistan conducted successful test explosions of atomic bombs, raising the specter of fratricide by nuclear war.
Sixty-five years after the acrimonious divorce between India and Pakistan, the border remains a throbbing wound of separation - yet a wound elemental to both nations' psyche. So is there no hope for lasting peace? There is, if you believe that small steps matter: in 2010, the commander in charge of the Pakistani Rangers announced that the aggressive nature of the Wagah ceremony would be toned down to reflect the desire for improved relationship between both countries. No details are available on the specifics. Did the sentries have their moustaches clipped? Or does that curt handshake last just a bit longer nowadays?
Frank Jacobs is a London-based author and blogger. He writes about cartography, but only the interesting bits.
 The earliest incarnation of the Grand Trunk Road, a storied route that roughly links the eastern and western lands of the subcontinent, is over 2,000 years old; its longest version was over 2,000 miles long, connecting Kabul and Chittagong (now in Bangladesh), via Peshawar, Lahore, Delhi, Varanasi and Dhaka. Over its long history, it's been called Uttarapatha ("The North Path"), Sadak-e-Azam ("The Great Road"), and the Long Walk. In India, the stretch between Delhi and the Pakistani border at Wagah is known as National Highway 1. It also coincides with the longest road of the Asian Highway Network, the 12,848-mile Asian Highway 1, (theoretically) connecting Tokyo and Istanbul.
 International travellers can make the crossing by car, bus or train: the Samjhauta Express between Delhi and Lahore passes through Wagah. The crossing at Munabao, further south, is only by train and closed to all but citizens of either country. There are also a few direct flights between the big cities in Pakistan and India. Before the Indo-Pakistani War of 1971, the border crossing was at Hussainiwala, about 40 miles south of Wagah. That crossing remains closed, but Hussainiwala also retains a lowering-the-flag ceremony.
 "Long Live Pakistan!" and "Long Live India!" Both are common expressions of nationalist fervor in either country.
 By Michael Palin, who filmed the ceremony on one of his circumnavigations of the globe. Those travels have earned him the presidency of the Royal Geographic Society (2009-2012; Mr. Palin was succeeded on June 11, 2012 by Prof. Judith Rees, Director at the London School of Economics). The Wagah border ceremony's comic-aggressive strutting has been compared to the courtship displays of peacocks, or to the antics of the Ministry of Silly Walks, as performed by Mr. Palin's fellow Python, John Cleese (in this clip, Mr. Palin applies to Mr. Cleese for a grant to develop his very own silly walk).
 Prime Minister Benjamin Disraeli called India "the brightest jewel in the crown" of the British Empire. Under his premiership, Queen Victoria was proclaimed empress of India, a title her successors kept until 1947.
 The term British "Raj," from the Hindi for "reign," describes the era of direct British rule over India, from 1858 (when the British East India Company's holdings were transferred to the Crown) to independence. Most of India was under direct British rule (60 percent of the total area, and as much as 75 percent of the total population), but there remained a few hundred princely states over which the British ruled only vicariously, through local maharajahs. At its greatest extent, the Raj encompassed not only present-day India (minus small French and Portuguese possessions like Pondicherry and Goa), Pakistan, Bangladesh and Myanmar, but also, for shorter periods, Aden (now part of Yemen), British Somaliland (now part of Somalia) and Singapore. Ceylon and the Maldives, although also under British rule, were never part of the Raj, nor were Nepal and Bhutan, which were bound by treaties to Britain, but retaining their independence.
 Nor did Gandhi himself survive independence for very long: on Jan. 30 1948, he was gunned down by a Hindu extremist who found his attitude toward Pakistan too "lenient."
 "Divide and rule," often ascribed to King Philip II of Macedon (382-336 B.C.), father of Alexander the Great.
 Mountbatten was also India's first post-independence governor-general, from 1947 to 1948. That by-now largely ceremonial post was abolished when India became a republic in 1950. Other non-republics within the British Commonwealth are still formally presided over by a royally appointed governor-general, who retains a rank similar to that of viceroy. Mountbatten, a cousin twice removed of Queen Elizabeth II and an uncle of her husband Prince Philip, was assassinated by the Irish Republican Army in 1979. Only last week did the queen, on her Diamond Jubilee tour of Northern Ireland, shake hands with the former I.R.A. commander Martin McGuinness (currently deputy first minister of Northern Ireland). Less constrained by the need to be diplomatic, Prince Phillip, who accompanied the queen to Ulster, was seen ostensibly to duck and run when approached by Mr. McGuinness.
 Both states had slight, but not overwhelming, Muslim majorities, and were to be partitioned; the eastern part of Bengal became East Pakistan (and after the 1971 war between India and Pakistan, Bangladesh).
 Some friction notwithstanding, notably a territorial dispute in the Great Rann of Kutch that contributed to the 1965 war between the two countries, but was resolved by arbitration in 1968 (Pakistan receiving 350 sq. mi, or 10 percent of its claim), and the downing in 1999 by India of a Pakistani patrol plane, after supposedly having strayed into Indian airspace.
 Also fought in Arunchal Pradesh, in India's far east. The line of actual control there coincides with the older McMahon Line.