Tallinn is a port city situated on the Baltic Sea and the capital of Estonia. Due to the access to the sea, the commercial traditions of the city date back to the 10th century. There are many historic monuments of religious architecture, associated with different faiths. The Lutheran Cathedral of the Blessed Virgin Mary, the Roman Catholic Cathedral of Saints Peter and Paul and Orthodox Alexander Nevsky Cathedral are the most important ones. The late medieval town hall, the Great Guild House, the 18th-century Kadriorg Palace - the former residence of Emperor Peter I the Great Alexeyevich are noteworthy as well. The Old Town of Tallinn, called Vanalinn, has preserved its historical atmosphere thanks to the historic tenement houses and medieval city walls, along with the original gates and towers.