Hohenschoenhausen Prison

They spied on everyone, did the Stasi. Thousands of members of the public, their own operatives, and even Margaret Thatcher. The Iron Lady was never at risk of seeing the inside of this prison, but plenty did - and plenty experienced the interrogation techniques used by a security force gripped by paranoia and guided by brutality. Now Berlin's Hohenschoenhausen prison is a national memorial, operating not just as a museum but also as an education centre (about half of its 350,000 visitors each year are students). It's always worth booking a tour, as many of them are led by former inmates with first hand experience of the regime.