At Russia's first ever museum of sex and erotica in St. Petersburg, inside a formaldehyde-filled jar is supposedly the foot-long severed cock of the Russian mystic Rasputin. There's no actual proof that the dick did indeed at one point belong to Rasputin, but that's the museum's claim and they're sticking to it.

From Metro UK:

Museum founder Igor Knyazkin has previously boasted of his prized possession: 'Having this exhibit, we can stop envying America, where Napoleon Bonaparte's reproductive organ is now kept.

'Napoleon's penis is but a small 'pod' - it cannot stand comparison to our organ of 30 centimeters.'

The veracity of Napoleon's severed penis is also unconfirmed, although a shrivelled item said to be the French leader's ex-phallus was sold to an American urologist at auction in 1977.

I think the only way to solve this mystery is to take the dick out of the jar, stab it, burn it, shoot it, wrap it in a rug and throw it into a frozen river. If it crawls out, it's Rasputin's penis.