president / was / Barack Obama / how long (2009 – 2017)
how long ago / the internet / become / popular / did (the 1990s)
how long / Marco Polo / stay / did / in China (17 years)
when / sink / did / the Titanic ( April 15, 1912)
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how long / Leonardo da Vinci / live / did (1452 – 1519)
when / the Statue of Liberty / finish / was (1886)
how long / did / World War I / last (4 years)
when / the first email / send / was (1971)
when / sign / was / the Declaration of Independence (July 4, 1776)
when / Google / founded / was (September 4, 1998)
when / did / Apple / the first iPhone / release (2007)
how long / the pyramids / take / to build / did (about 20 years)
when / Netflix / start / did (1997)
how long / dinosaurs / ago / live / did (about 65 million years)
how long / the Roman Empire / exist / did (27 B.C. – A.D. 476)
the first / was / when / Harry Potter movie / released (2001)
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the moon landing / how long / was / ago (1969)
when / start / did / World War II (1939)
when / the Eiffel Tower / build / was (1887 – 1889)
when / the Berlin Wall / fall / did (November 9, 1989)
when / born / was / Albert Einstein (1879 – March 14)
when / on tv / be / the first episode of Friends (September 22, 1994)