A Berlin museum has lifted the lid on a new exhibit celebrating the long history of gay sex in public restrooms.

Fenster zum Klo: Public Toilets, Private Affairs, now on display at Schwules Museum, features unsanitized photographs by Marc Martin. In an introduction to the show, the French photographer reveals that some of his earliest sexual experiences were in these thrilling urban spaces.

"These places, where men were constantly coming and going, were instrumental in my sexuality, aroused my desires and quenched my curiosity," Martin writes. "In there, I also had the most unlikely, unexpected encounters."

Although Martin acknowledges that sexual acts in public toilets "remain more a source of shame than pride" within the gay community, he considers them "sites of unbridled freedom."

"Differences were blurred and otherwise separated cultures briefly mixed," Martin continues. "Despite being disparaged as sleazy and dirty, they allowed for immediate, anonymous sexual contacts. They were a godsend to those who could not entertain at home and expose their sexual proclivities to the outside world."

"The necessity of gay men to 'hide' and meet in 'secret' places such as parks and public toilets is an important aspect of gay history," Schwules spokesman Dr Kevin Clarke tells Gay Star News. "So it’s important for us, as a museum, to present this topic with as much background as possible, for a younger generation accustomed to Grindr and other apps to understand how homosexual men organized their sex life decades ago, but also to make clear the incredible dangers they faced from police, criminals and blackmailers."

The exhibit has been officially sponsored by Berlin’s public transport service, Berliner Verkehrs-Gesellschaft. BVG even granted Martin access to public toilets in its subway stations that have been closed for decades.

Martin’s photos, accompanied by quotes about urinals from literary minds such as Jean Genet and Rimbaud, are also complemented by various talks and film screenings on the subject.

"From poetry to pornography, his work bears witness to the generation of today, of a type of sexual interaction that has virtually disappeared now," reads a description of Martin's exhibit. "Glorious or shameful, our good old cottage toilet no longer needs to blush about its past."

See more photos below.

Marc Martin: Fenster zum Klo - Public Toilets, Private Affairs runs through February 5, 2018, at Schwules Museum in Berlin.