When the Hotel Viru was built in 1972, it was not only Estonia’s first skyscraper, it was the only place for tourists to stay in Tallinn – and we mean that literally. Having all the foreigners in one place made it much easier to keep tabs on them and the locals they had contact with, which is exactly what the KGB did from their 23rd-floor spy base. The hotel offers fascinating tours of the facility in various languages; bookings essential.