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

Now Playing: Pentagon officials remark on strikes in Syria

Now Playing: Strikes will establish a strong deterrent of chemical weapons: Trump

Now Playing: US launches strike on Syrian chemical weapons storage facilities

Now Playing: Special Report: Pentagon briefing on Syria strike

Now Playing: Pentagon says Syria strike specifically hit 3 targets

Now Playing: SPECIAL REPORT: Trump orders military strike on Syria