Paul Whelan, a US citizen who was arrested by Russian authorities in Moscow and charged with espionage, is being held in Lefortovo Prison.

Lefortovo is one of the oldest and most infamous detention facilities in the Russian capital.

The ex-KBG prison has long been used to house dissidents and foreign spies.

Joseph Stalin's secret police tortured prisoners at Lefortovo and there are many legends about the horrifying conditions in the prison during the Soviet era.

Paul Whelan, a US citizen, was detained in Moscow by Russia's Federal Security Service (FSB) on New Year's Eve and charged with espionage.

Whelan, 48, is now being held in one of the oldest and most infamous prisons in Moscow.

Here's a look at the notorious Lefortovo Prison.

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