The center of Baku is the old town, which is also a fortress. In December 2000, the "Walled City of Baku with the Shirvanshah's Palace and Maiden Tower" (called the "inner town") became the first location in Azerbaijan classified as a World Heritage Site by UNESCO. Most of the walls and towers, strengthened after the Russian conquest in 1806, survive. This section is picturesque, with its maze of narrow alleys and ancient buildings. Wander the cobbled streets past the Palace of the Shirvanshahs, two caravansaraies (ancient inns), the 11th century Maiden Tower (nice view of the harbor), the baths and the Djuma Mosque (it used to house the Carpet and Applied Arts Museum, but now is a mosque again; the carpets got moved to the former Lenin museum). The old town also has dozens of small mosques, often without any particular sign to distinguish them from the next building.