Sillamäe is the most enigmatic town in the province of Ida-Virumaa. In the Soviet era, its existence was effectively deliberately hidden by the authorities, who undertook nuclear research here. To find out more, visit the museum dedicated to this episode in local history. The second half of the 20C saw Sillamäe grow rapidly and it is today home to many industrial enterprises. Its straight avenues lined by neo-Classical residences and its seafront give the town a certain charm.