Nazi Germany sent between 5,000 and 15,000 gay men and lesbians to concentration camps. There, they were marked out with a downward pointing pink triangle and a great many of them died. In more recent years, the pink triangle has been reclaimed as a symbol of the gay rights movement – pointing upwards.

Julius Caesar returned from his campaigns in Gaul (modern France) to celebrate his triumph in Rome. It was customary for soldiers in the victory procession to mock their general. Caesar’s soldiers teased him by hinting at his love affair with an Asian king (that Caesar supposedly had when he was a lad).

Few people know that democracy started because of a same-sex relationship. A guy called Aristogiton was dating Harmodius. Another man called Hipparchus tried to steal Harmodius from Aristogiton, but was turned down so told his brother – the tyrant king. The young couple then tried to assassinate Hipparchus and the king, but were killed. Soon, though, other people got angry and overthrew the king and started the first democracy.

Alan Turing was an English computer scientist who famously broke the Nazi ‘enigma code’. But, he was also convicted for ‘indecency’ in 1952. Part of his punishment was a hormonal treatment that made him impotent and he lost his security clearance to work in intelligence. Two years later, Turing killed himself. In 2013, Queen Elizabeth II granted Turing a pardon.

Many Roman emperors had both female and male partners. But the most famous palace boy was a hottie called Antinous, partner of emperor Hadrian. When he mysteriously died, Hadrian was devastated, and wanted his boyfriend to be remembered forever. He made Antinous a god and had temples and statues built all over his empire.

Britain’s most famous bard is best known for his plays, but he also wrote 154 love sonnets which were published in 1609. The first 126 were addressed to an un-named young man – including Sonnet 20 which wishes the young man were a young woman. The last 28 sonnets are addressed to a woman.

These books couldn’t be more different – but they’ve all caused controversy. The Well of Loneliness is the story of an Englishwoman called Stephen who falls in love with a woman called Mary. Leaves of Grass is an experimental poetry collection addressing the author’s relationship to himself and his country. And Tango Makes Three is a children’s book about penguin parenthood.

Ireland were the first country in the world to introduce marriage equality following a popular vote. 62.1% of the people who voted supported the motion. However, in Northern Ireland (part of the UK), marriage is not available for same-sex couples – only Civil Partnerships.

When cops tried to conduct a routine raid on a bar called 'The Stonewall Inn' in New York that was popular with the gay community in June 1969, they lost control. Riots ensued for several nights. In the following months, people came together to campaign for their rights and in June 1970 the first gay pride marches took place in the US.

Nepal is the only country in Southern Asia where it is legal to have sex which someone of your own gender. In other countries in the region, the penalty varies from imprisonment, house arrest to whipping to death.