Whilst in Dushanbe clients should visit Nurek, formerly a restricted zone during the Soviet era. Included is a visit to Nurek Dam, constructed in 1961 on the River Vakhsh, which is still the world's tallest hydroelectric dam (310m) and provides more than 90% of Tajikistan's electricity. A narrow road winds up to the top of the dam, affording spectacular views of the Pulisangin Canyon. The town of Nurek is a fascinating preserved piece of Soviet history where a statue of Lenin still stands in the central square. There is a small but interesting museum dedicated to the construction of the dam, and the town's library contains signed copies of books by many prominent Soviet personalities, including the cosmonaut, Yuri Gagarin.