By stunning the world after seven decades of war and enmity, the projected face-to-face rendezvous between U.S. President Donald Trump and North Korean leader Kim Jong Un would immediately take its place in the historic pantheon of electrifying summits between sworn foes.
From World War Two's Yalta gathering through U.S.-Soviet summits in the Cold War, President Nixon's trip to Chairman Mao's China and various attempts to forge peace among Israeli, Egyptian and Palestinian leaders, the art of the summit has long been a rare and rarified moment where the world stops agape.
Sometimes a summit becomes notorious in history and not for the right reasons — as in British Prime Minister Neville Chamberlain's summit with Adolf Hitler in 1938 in Munich that has come to symbolize the very concept of appeasement.
Some are remarkable in that they bestow legitimacy, whether intended or not, on a foe that had been a pariah.
There are also those cases that are remarkable in having never happened: It is striking, but perhaps not surprising, to consider that Iraqi leader Saddam Hussein never met either of the President Bushes, nor did President Franklin D. Roosevelt meet Hitler.
Although the moment, protagonists and locations become enshrined in history books, major summits hold no guarantee of further progress. In some cases, the summit is as good as it gets as relations remain stagnant or plummet further.
Here's a look at some of the key summits that have left an indelible mark on the collective global memory.
THE KOREAS - FALSE DAWNS
The announcement that Trump and Kim — two leaders who have traded threats of nuclear annihilation and person insults — will sit down together completely eclipsed word that came out shortly before that South Korea's President Moon Jae-in will hold a summit with the North's leader in April.
That in and of itself was major news: The leaders of the two Koreas have only met twice before.
The first time came in 2000 between Kim Jong Il, the late father of the current leader of the North, and South Korea's then-president, liberal Kim Dae-jung. A broadly smiling Kim Jong Il tightly grabbed the hands of Kim Dae-jung at the Pyongyang airport, and the next three days led to an agreement to resume family reunions and a deal on joint economic projects, though those have since stalled.
The second inter-Korean summit came in October 2007 between Kim Jong Il and Roh Moo-hyun, Kim Dae-jung's successor and the current president's political mentor.
In a highly symbolic moment, Roh crossed the Demilitarized Zone and met with Kim in the North Korean capital Pyongyang. There, they agreed to pursue a peace treaty to formally end the Korean War and reached a set of cooperation projects.
But most of the accords were shelved after Roh's single 5-year term ended months later. He was replaced by a conservative who took a harder line over the North's nuclear ambitions.
YALTA CONFERENCE - ONE WAR ENDS AND ANOTHER BEGINS
The grandfather of them all. U.S. President Franklin D. Roosevelt, British Prime Minister Winston Churchill and the Soviet Union's Josef Stalin came together to plan for a postwar future for a Europe in ruins and try to hasten an end to the conflict in the Pacific. Stalin agreed to enter the war to help defeat Imperial Japan. Roosevelt and Churchill allowed for Soviet influence over lands Russia lost to Japan decades earlier.
Initially hailed as a major success, the conference later came to be viewed by some as the moment that the United States ceded too much influence to the Soviets and the trigger for the Cold War.
U.S.-SOVIET UNION/RUSSIA - THE COLD WAR ERA AND BEYOND
Soviet leader Nikita Khrushchev and President John F. Kennedy met in Vienna, Austria in 1961. There was plenty of fanfare, including a high-profile interaction between first ladies Nina Khrushchev and Jacqueline Kennedy. But U.S. government accounts of the summit suggest it was extremely tense. Kennedy was largely steamrolled by the Soviet leader, who demanded an immediate treaty to reunify Germany under terms unfavorable to the U.S. The collapse raised the specter of an actual war between the two nuclear-armed foes. Two months later, the Berlin Wall went up.
President Nixon flew to the Soviet capital in 1972, the first visit to Moscow by a sitting U.S. president, for a week of meetings with Soviet leader Leonid Brezhnev. The two leaders clinched agreements limiting ballistic missiles and slowing the nuclear arms race and smaller deals on education, science, maritime coordination and public health. The gathering would later be viewed as an inflection point in the Cold War.
Another breakdown between leaders, this time in the Icelandic capital, came in 1986 between the U.S.' Ronald Reagan and the Soviets' Mikhail Gorbachev. Hastily arranged with low expectations, the summit grew in scope to the point it appeared a major arms reduction deal might be reached. The two leaders were pictured in iconic photos smiling together at Hofdi House in Reykjavik. But in the end, they failed to seal an accord or evenagree on a date for a follow-up summit in the U.S.
A decade after the fall of the Soviet Union, President George W. Bush famously looked into Russian President Vladimir Putin's eyes. "I was able to get a sense of his soul — a man deeply committed to his country and the best interests of his country," Bush said afterward.
The lavish praise came to be seen as a sign of naiveté about the Russian leader and former KGB operative, who would go on to flummox successive American presidents.
NIXON TO MAO'S CHINA - PING PONG DIPLOMACY IS A GAME CHANGER
In 1972, President Nixon made the historic and unprecedented journey to meet Chairman Mao in part paved by an American ping pong delegation who traveled to Beijing the year before.
Their historic handshake was as much about countering the Soviet threat as building trade and cordial relations between the two countries. China felt directly threatened by the Soviets at the time, and Nixon was thought to have parlayed the nascent relationship as a counter to Moscow over arms control negotiations.
Over the decades, successive U.S, presidents have held summits with their Chinese counterparts at home and abroad. President Trump most recently hosted President Xi Jinping in 2017 at his Florida estate and was welcomed by Xi to China with fanfare later the same year. But threats of a trade war following Trump's decision to levy stiff new tariffs on aluminum and steel now loom.
ISRAEL, EGYPT AND THE PALESTINIANS - BREAKTHROUGHS BUT MANY MORE FALLDOWNS
When Egyptian President Anwar Sadat visited Israel in 1977, it signaled a new beginning for the battle-weary nations that would transform the region. After decades of animosity and just four years after a bitter war, Sadat came with a historic offer of peace.
Israelis watched in disbelief as Sadat descended from an Egyptian plane on Nov. 19 and set foot on Israeli soil. Images of the Egyptian leader shaking hands with his old enemies, including the legendary general Moshe Dayan and former Prime Minister Golda Meir, and speaking at Israel's parliament brought euphoria to Israelis and sent shockwaves throughout the region.
The visit set the tone for the Camp David peace summit which led to the Egyptian-Israeli Peace Treaty Signing Ceremony in 1979 where Sadat famously declared: 'Let there be no more wars or bloodshed between Arabs and the Israelis.'
The peace treaty was the first between Israel and an Arab country and relations between the former enemies have remained intact.
It would also lay the groundwork for a series of later Mideast summits, most famously a 1993 White House meeting where Israeli Prime Minister Yitzhak Rabin and Palestinian leader Yasser Arafat signed an initial peace agreement.
The two longtime adversaries had never met before and Rabin looked clearly uncomfortable as President Bill Clinton brought them together to shake hands. That awkward handshake remains an iconic image of Israeli-Palestinian history.
But the peace process has largely gone nowhere since the 1995 assassination of Rabin. A 2000 summit between Arafat and Israel's Ehud Barak broke up amid dashed expectations, followed by a years-long violent uprising. Palestinians have self-rule in Gaza and in enclaves of the West Bank but negotiations for a final deal to end the occupation and establish a Palestinian state have repeatedly fallen apart amid bouts of violence and recrimination.