US president Donald Trump and Korean leader Kim Jong Un shake hands during their previous meeting last year (Picture: PA).
President Donald Trump and North Korean leader Kim Jong Un are in place ahead of their second summit on Wednesday to address perhaps the world's biggest security challenge.
Mr Trump arrived late on Tuesday in Air Force One after a long flight that included refuelling stops in the UK and Qatar, while North Korean leader Kim Jong Un's armoured limousine arrived in Vietnam's capital Hanoi earlier on Tuesday.
Mr Kim's journey started consisted of a long train ride from Pyongyang through China up to a Vietnamese border town.
The US president is set to fly to Hanoi from Washington.
Mr Kim will be staying at the Melia Hotel, where soldiers, police forces, journalists and crowds of people awaited his arrival.
As he arrived at the location, the North Korean leader shook hands with Vietnamese officials.
A crowd gathered along the road near the station to wave North Korean flags and bouquets of flowers.
Kim Jong Un stepped into a black limousine that was then surrounded by bodyguards who ran alongside their leader as he left the station.
What is the meeting about?
The summit is the second meeting between the US president and the North Korean leader.
The previous summit, a historic first between the US and North Korea, was held in June 2018 in Singapore. It saw both leaders discussing steps to achieve denuclearisation.
Following last June's meeting, Mr Trump predicted that he and the North Korean leader would have a "terrific relationship".
Regardless of Mr Trump's optimism following the previous international summit with North Korea, there have been warnings from both the United Nations and the US Secretary of State Mike Pompeo reporting that the nuclear programmes had not stopped.
This meeting will follow up on the previous one and is meant to deal with one of Asia's biggest security challenges: North Korea's pursuit of a nuclear programme that stands on the verge of viably threatening any target on the planet.
"With complete denuclearization (sic), North Korea will rapidly become an Economic Powerhouse. Without it, just more of the same," tweeted President Trump on Monday.
"Chairman Kim will make a wise decision," said the US president.
A rushed summit?
Officials in Hanoi said they only had about 10 days to prepare for the summit.
This is much less than the two months notice Singapore had before the first Trump-Kim meeting last year.
However, Vietnamese officials still vowed to provide airtight security for the two leaders.
"Security will be at the maximum level," Vietnamese deputy minister of foreign affairs Le Hoai Trung told reporters.
The ultra-tight security will be appreciated by North Korean authorities, who are extremely vigilant about the safety of Mr Kim, the third member of his family to rule the North with absolute power.
Roads on Tuesday were shut down from the border with China all the way to Hanoi, 106 miles away.
There are high expectations for the Hanoi summit after a vague declaration at the first meeting in June in Singapore that disappointed many.
Speaking to senior aides in Seoul, South Korean president Moon Jae-in said that the Trump-Kim talks would be a critical opportunity to achieve peace on the Korean Peninsula.
Mr Moon has met Mr Kim three times last year and is lobbying to revive nuclear diplomacy between the US and North Korea.
The South Korean president is eager for a breakthrough that would allow him to push ambitious plans for inter-Korean engagement, including lucrative joint economic projects that are held back by US-led sanctions against the North.
"If President Trump succeeds in dissolving the world's last remaining Cold War rivalry, it will become yet another great feat that will be indelibly recorded in world history," Mr Moon said.