Azerbaijan, the nation and former Soviet republic, is bounded by the Caspian Sea and Caucasus Mountains, which span Asia and Europe. Its capital, Baku, is famed for its medieval walled Inner City. Within the Inner City lies the Palace of the Shirvanshahs, a royal retreat dating to the 15th century, and the centuries-old stone Maiden Tower, which dominates the city skyline.
Baku is also known for contemporary landmarks including the Heydar Aliyev Center, a curvaceous structure designed by Zaha Hadid and used for cultural events. Outside town are the reconstructed Bibi-Heybat Mosque, a pilgrimage site, and the Azerbaijan Carpet Museum, housing a vast collection of ornate, locally made carpets. To the south is Gobustan National Park, surrounded by hundreds of mud volcanoes and perforated with caves featuring rock engravings from the Stone and Bronze ages. In the remote north, the mountain village Khinalug is a hiking destination and former center of the Zoroastrian faith.