Now Playing: North and South Korean leaders cap 3-day summit with sacred mountain trek

Now Playing: Pups on parade, a holy day, Trump visits North Carolina: World in Photos

Now Playing: Vladimir Putin takes a breath and fires sniper rifle

Now Playing: South Korean president wraps up 3-day Pyongyang visit

Now Playing: North and South Korean leaders meet for 3rd summit

Now Playing: Korean leaders agree to enter an 'era of no war'

Now Playing: Philippine landslides, Korean leaders meet and penguins: World in Photos

Now Playing: Young boy arrested for putting needles in fruit in Australia

Now Playing: 3 injured when car drives into crowd near London mosque

Now Playing: Trump reacts to new North Korea denuclearization promises

Now Playing: Korean leaders sign agreement for North Korea to take further steps to denuclearize

Now Playing: President Trump holds a joint news conference with Poland's president

Now Playing: Leaders of South and North Korea meet for 3-day summit

Now Playing: SpaceX announces 1st customer to orbit the moon

Now Playing: Proposal at the Emmys, storm devastation, a Korean summit: World in Photos

Now Playing: Korean leaders meet for 3rd summit

Now Playing: 1st private citizen purchases ride around the moon

Now Playing: North and South Korean leaders meet for 3rd summit

Now Playing: Historic announcement from SpaceX

Now Playing: Duchess Meghan helps launch a cookbook for charity