Now Playing: Gulf Oil Spill: Larger Than We Know?

Now Playing: Who's Responsible for Gulf Oil Spill?

Now Playing: New details emerge on how the Texas school shooting was carried out

Now Playing: President Trump stands by his claims that his campaign was spied on by the FBI

Now Playing: A look inside the world famous Kew Gardens

Now Playing: New details from the reception and parties following the royal wedding

Now Playing: Time magazine calls Harry and Meghan "modern royals"

Now Playing: Italian actress Asia Argento slams Harvey Weinstein at the Cannes film festival

Now Playing: VIP list revealed! Royal Wedding celebrity guests arrive in high fashion style

Now Playing: Royal wedding live coverage

Now Playing: What we know about the Sante Fe High School alleged shooter

Now Playing: The unofficial colors of the royal wedding? Spring-inspired blue and green!

Now Playing: Americans threw watch parties to catch the royal wedding

Now Playing: Harry, Markle include both tradition and personal touches in the ceremony

Now Playing: Harry, Markle do things their way with a non-traditional royal wedding

Now Playing: Some of Hollywood's brightest stars attend the royal wedding

Now Playing: Harry, Markle ride storybook-style horse-drawn carriage through Windsor

Now Playing: Markle's journey from American actress to member of the British royal family

Now Playing: A look at Markle's royal wedding dress

Now Playing: A look at the royal wedding cake