Narva is an ancient city located on the border of Estonia whose exact founding date is unknown but was first mentioned in 1171. Through the 16th century it served as an important trading hub between East and West. The city saw much construction and development of fortifications in the 17th century when it was part of the Russian state. Notable landmarks included the medieval castle and defensive structures, the Gothic-Baroque style old town centered around the large Town Hall square, and six large bastions surrounding the city with underground tunnels and casemates for defenders. The old town of Narva was destroyed in a 1944 Soviet bombing campaign during World War II.