Hanoi prepares for US-North Korea summit Video

Now Playing: Trump prepares for 2nd summit with Kim Jong Un

Now Playing: President Trump departs for Vietnam for second summit with Kim Jong Un

Now Playing: Hanoi prepares for US-North Korea summit

Now Playing: The Oscars, Carnival celebrations and a newborn giraffe: World in Photos, Feb. 25

Now Playing: Vatican wraps up historic summit

Now Playing: Meghan and Harry’s trip to Morocco

Now Playing: Across the Pond: VP Mike Pence to meet Venezuela’s opposition leader

Now Playing: Trump leaves today for second summit with Kim Jong Un

Now Playing: Pope declares ‘all-out war’ against abuse

Now Playing: Crisis in Venezuela worsens as military blocks US aid

Now Playing: Pope Francis declares ‘all-out’ war on abuse

Now Playing: Prince Harry and Meghan Markle travel to Morocco

Now Playing: Summit ‘will be a dud’ if Trump claims success without ‘actionable activity’: Bossert

Now Playing: VP Pence to meet with Venezuelan opposition leader Juan Guaido

Now Playing: Two planes crash within minutes of each other

Now Playing: Violence erupts between Venezuelan National Guard and demonstrators

Now Playing: Violent protests at Venezuela’s borders

Now Playing: North Korean leader Kim Jong Un begins long journey to Vietnam

Now Playing: The Vatican summit to focus on accountability

Now Playing: Stunning scene as starlings fly in Somerset sky