Hamburg's St. Pauli is one of the world's most famous red light districts. It attracts around 20 million visitors a year, but it's also a bit smelly because, after a night on the tiles, a good number of those visitors urinate in public places. Now, in a fit of poetic justice, the walls of St. Pauli are being upgraded so they retaliate on micturators in kind.

Almost every major city has a problem with public urination, and party areas like St. Pauli can often seem so much like visiting the inside of a chamber pot. This is particularly distressing for the merchants and residents of the area who have to put up with the stains and smell of wee on a daily basis.

But now, according to Julia Staron of Interessengemeinschaft St Pauli (an interest group for companies and businesses based in St. Pauli), it's "pee-back time." Prohibitions and fines haven't worked very well, so the local authorities are giving chemistry a try. Walls in the district were sprayed with Ultra-Ever Dry super-hydrophobic, oleophobic nano-coating, which is so water (and pee) repellant that urinating on a treated surface becomes a shoe-wetting, trouser-soaking exercise.

If you are visiting St.Pauli and get caught short, the video below warns that not all treated walls have warning signs posted.

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