Vladimir Putin is no stranger to superpower summits. Over the decades, as president or prime minister, he's held high-stakes meetings with five American presidents. His encounter withDonald Trumpon Friday in Alaska will be the first of Trump's second term and maybe the most significant since theircontroversial2018 meeting in Helsinki, Finland. This time, war and peace are urgently at stake as Trump has made it a priority to end the war in Ukraine. Trump's Aug. 8 deadline for Putin to agree to a ceasefire with Ukraine or face severe sanctions has come and gone without any peace deal. MORE: Trump warns Russia of 'severe consequences' if Putin doesn't agree to stop war The expected one-on-one meeting in Alaska marks Putin's first trip to the U.S. since 2015 and hiseighth overallas president -- a post the former KGB officer has held since late 1999, apart from 2008-2012 when he served as prime minister. Although he's met with every U.S. president since Bill Clinton, the meetings have been less frequent in recent years as he's been considered something of an international pariah, following the Kremlin's illegal annexation of Crimea in 2014, military actions in Syria in 2015 and Russia's interference in the 2016 presidential election. No U.S. president hastraveled to Russiasince 2013, when Barack Obama attended the G20 economic summit in St. Petersburg. Here's a look at memorable moments between the Russian president and his American counterparts. The two leaders had previously met while Putin served as prime minister, though their first summit came as Clinton's presidency was coming to an end and the new Russian president was just coming into power. The two met in Moscow in June 2000, nearly a decade after the end of the Cold War, and largely discussed arms control. On his assessment of Putin, Clinton said at a press briefing, "I think he is fully capable of building a prosperous, strong Russia while preserving freedom and pluralism and the rule of law. It's a big challenge. I think he's fully capable of doing it." On Clinton, Putin called him a "very experienced politician." "In my mind, we've established now not only good business ties, but also personal relations. For me, President Clinton is a person who is a very comfortable and pleasant partner in negotiations," Putin said. Bush and Putin held their first summit in Slovenia in June 2001. Following two hours of meetings, Bush said it was an "important step in building a constructive, respectful relationship with Russia." When asked whether he could trust Russia, Bush famously said of Putin that he "looked the man in the eye" and "found him to be very straightforward and trustworthy." "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. On their meeting, Putin said he had a "very interesting and positive" discussion with Bush, who "as a person who has studied history, proposed a very global, wide-scale approach and view to history." Bush would go on to meet with Putin in Russia multiple times throughout both terms of his presidency, including a 2002 visit to Moscow where they signed a treaty to reduce the number of nuclear warhead arsenals held by both countries. Putin also visited the U.S. several times, including traveling to Bush's ranch in Texas and family home in Kennebunkport, Maine, which often hosted heads of state during the Bush administration. Their relationship seemed to grow more strained, including following the U.S. invasion of Iraq in 2003, which Moscow opposed. During an informal meeting, the two had a more tense exchange during Bush's historic trip to Beijing for the 2008 Summer Olympics, where Bush confronted then-Prime Minister Putin about Russia's ongoing attack on its neighbor, Georgia. Putin continued to serve as prime minister during the first few years of Obama's presidency -- during which he and Obama met for the first time along with then-Russian President Dmitry Medvedev in Moscow in July 2009. During that visit, Obama said his interest was in dealing with his counterpart, though said he wanted to reach out to Putin "and all other influential sectors in Russian society so that I can get a full picture of the needs of the Russian people and the concerns of the Russian people." "Our interest is dealing with the Russian government as a whole in order to achieve the improved bilateral relationship that I think can be accomplished," Obama said. Putin returned to the presidency in 2012. A year later, the White Housecanceleda planned summit with Putin in Moscow, citing Russia's "disappointing decision" to grant asylum to national security leaker Edward Snowden and a lack of progress in the U.S.-Russia bilateral agenda. Russia's invasion and illegal annexation of Crimea in 2014 and support of Syrian President Bashar al-Assad, whom the U.S. had called to be removed, continued to strain relations. Obama and Putin had theirfirst formal meeting in two yearsin September 2015 at the U.N. General Assembly in New York City, in what was Putin's last visit to the U.S. until the planned Alaska summit. MORE: NATO Secretary General Rutte says Trump-Putin summit is about 'testing Putin' Trump and Putin met for the first time as presidents in July 2017 during a G20 summit in Hamburg, Germany. Though one of their more notable summits came a year later, in Helsinki in July 2018, when they talked behind closed doors for nearly two hours. In an extraordinary press conference afterward, while standing next to Putin, Trumpseemed to acceptthe Russian president's denial of election interference over the findings of U.S. intelligence. (Earlier this month, Attorney General Pam Bondi ordered a Justice Department investigation into the Obama administration intelligence community's handling of claims Russia interfered in the 2016 election.) "[Putin] just said it's not Russia. I will say this. I don't see any reason why it would be," Trump said. "I have great confidence in my intelligence people, but I will tell you that President Putin was extremely strong and powerful in his denial today," he later said. Asked why Trump should believe Russia's denial of election interference, Putin said during the briefing, "You can trust no one," and called the U.S. intelligence agencies' findings "utter nonsense." He said he wanted Trump to win "because he talked about bringing the U.S.-Russia relationship back to normal." Following significant bipartisan criticism back home, Trump walked back his comments the next day, saying he misspoke and that he meant to say, "I don't see any reason why it wouldn't be Russia." The summit also drew concerns for the lack of aides or other government officials, only interpreters, in the room with Trump and Putin. Later that year, Trumpabruptly canceleda planned meeting with Putin on the sidelines of the G20 summit in Argentina, citing Russia's refusal to release Ukrainian Navy ships and sailors it seized near Crimea. Biden met with Putin once during his presidency, in Geneva in June 2021. He had called for thehigh-stakes meetingwith Putin, alarmed about ongoing Russian military aggression toward Ukraine. Biden said the summit was "positive" and that he "did what I came to do." Putin called the over three-hour talk "quite constructive," though he contended that Russia's military aggression toward Ukraine was not the business of the U.S. Less than a year later, in February 2022, Russia invaded Ukraine, a war that has been waged ever since.