The Cultural Kilometre terminates outside Estonia’s most astounding museum attraction, the Air Harbour, a huge hangar built by the Russians in World War I to house a fleet of sea planes. A masterpiece of modern construction, this cavernous concrete space was reopened in 2012 as an extension of the Maritime Museum. A system of raised walkways takes you past the exhibits – including fishing boats, mines, a replica World-War-I biplane and naval guns. The pièce de résistance is the Lembit submarine, built for the Estonian navy in Barrow-in-Furness in the 1930s. Outside, ice-breaker Suur Toll and several other ships are moored.