Now Playing: Show explores the world beneath the ocean's surface

Now Playing: Trump pick for secretary of state continues fight for confirmation

Now Playing: Coast guard rescues owners, dog during Wales' high tide

Now Playing: Trailer: 'White Gold'

Now Playing: Mexico vacationers scrambling to get back to US after airline cancels flights

Now Playing: What site of suspected chemical attack in Syria looks like 10 days later

Now Playing: Cuba without a Castro: What comes next?

Now Playing: Surfers attacked by sharks in 2 separate incidents in Australia

Now Playing: Koala rescued from Australian wildfires

Now Playing: Weekend Rewind: Syria air strikes

Now Playing: The latest on Syria

Now Playing: White House presents report it says proves Syria conducted chemical attack

Now Playing: Unanswered questions around the attack on Syria

Now Playing: Syria denounces the U.S.-led attack

Now Playing: Trump calls military action on Syria a 'perfectly executed strike'

Now Playing: US launches retaliatory airstrikes against Syria

Now Playing: Destruction in Syria in the wake of airstrikes

Now Playing: US, France and Britain launch missile strikes on Syrian weapons facilities

Now Playing: US and allies launch attacks on Syria

Now Playing: Iran, Russia should not associate with mass murder of innocent people: Trump