In 2012, Donald Trump running for the presidency of the United States of America was a popular joke. A funny tagline for things too ridiculous to be considered. Today, with the exception of the xenophobic crowd that voted for him, nobody's laughing.
In the year 2000, the Democrats' Al Gore won the popular vote but it was the Republicans' George W Bush who took over the Oval Office. This has happened three times before as well. According to npr.org, Andrew Jackson won the popular vote in 1824 but lost to John Quincy Adams as did Samuel Tilden in 1876 (who lost to Rutherford B Hayes) and Grover Cleveland in 1888 (who lost to Benjamin Harrison).
What is this strange behaviour you ask?
Well, in America, it is not the number of votes but rather the electoral college which determines the presidency.
Electoral College? Say what?
The American Constitution has assigned each of the 50 states in America electors which total the state's Senate and House of Representatives. The number of electors vary from state to state - for instance, Vermont has 3, Arizona has 11, Texas has 38 - and equal a total of 538 electoral votes in all.
When the American public votes, they do not vote directly for a presidential candidate, but for the electors of a party of their choosing. In case of the 2016 US elections, the choice was between the Democratic Party, Republican Party, Green Party, Libertarian Party and an Independent candidate.