Tashkent, the ''City of Stone'' and the capital of Uzbekistan, is an ancient city that dates back to the 5th century BC city called Chach, though little remains from that time. Today, Tashkent is one of the most modern cities in Central Asia, with a liberal attitude, an efficient infrastructure, a varied and exciting nightlife, as well as bustling commerce and trade. In fact, Tashkent is the only city in Central Asia with a metro system. The city is located in the north-east region of Uzbekistan, at the confluence of the Chirchik River with its tributaries, between Shymkent and Samarkand. To the north of the city, it is possible to see the mountains of Big and Small Chimgan. Tashkent has a continental climate, with long dry summers, and short but cool winter. It is unfortunate that not much remains of Tashkent's architectural heritage, as the city was greatly damaged and partially destroyed in the 1917 revolution, and the 1966 earthquake. However, the city is still rich with some 16th century monuments, as well as numerous museums, vibrant traditional markets, and Soviet-era edifices. Some of the most important sights include: Mausoleum of Kukaldash, Madrassah of Barrak Khan, Chorsu Bazaar, Independence Square, Telyashayakh Mosque or Khast Imam Mosque (which contains the oldest extant Qur'an in the world, dating back to 655 AD), Prince Romanov Palace, Yunus Khan Mausoleum, Alisher Navoi Opera and Ballet Theatre, The Bolshoi Navoi Theater, Fine Arts Museum of Uzbekistan, Museum of Applied Arts, History Museum, Amir Timur Museum, and Navoi Literary Museum.