Now Playing: Deadly earthquake rocks Japan

Now Playing: Mexico fans trigger earthquake sensors with World Cup celebrations

Now Playing: Meghan Markle's father speaks out after royal wedding

Now Playing: Earthquake near Osaka kills at least 4 people

Now Playing: What is dragon boating?

Now Playing: American remains missing in Vietnam after arrest during protest

Now Playing: 2 suicide bombings end 3 days of peace in Afghanistan

Now Playing: Speeding taxi runs into crowd of tourists on Moscow sidewalk

Now Playing: Children watching the World Cup celebrate after goal

Now Playing: Trump administration picks Texas city as new tent site for immigrant children

Now Playing: Family of American student arrested in Vietnam speaks out

Now Playing: North Korean defectors comment on summit between Trump and Kim Jon Un

Now Playing: Adele joins Grenfell Tower mourners

Now Playing: Stephen Hawking's ashes buried at Westminster Abbey

Now Playing: Caught on camera: Banksy print worth $45K stolen from Toronto art exhibit

Now Playing: Tents pop up along Mexican border for migrant children housing

Now Playing: A look inside the US's largest facility for undocumented children

Now Playing: South Korean foreign minister 'surprised' by Trump

Now Playing: Roller coaster near D.C. strands riders

Now Playing: 3 inmates escaped jail in Illinois; 1 caught