After the Soviets built Tallinn’s luxurious, but imposing, Hotel Viru in the 1970s, Estonians joked that the building was made of microconcrete, as in concrete and microphones.

Few people were ever allowed on the hotel’s top floor, which the Soviet managers insisted contained only technical rooms. When the KGB fled the country in the early 1990s, the newly liberated Estonians discovered that the technical rooms housed elaborate, vintage James Bond-esque listening equipment.

The hotel’s new owners kept the rooms exactly as the KGB left them. On the door of those technical rooms is now written “There’s nothing here” in both English and Estonian, which alludes to the official answer given when anyone asked what was behind the door. Visitors can take guided tours that focus not only on the more absurd elements of living in a surveillance state, but on the strange history of the hotel, which includes prostitution, espionage, and some of the best chicken to be had during the occupation.