Istanbul Attractions

Built during the 6th century on orders from the Byzantine emperor Justinian, the Ayasofya (aka Hagia Sophia, or the Church of the Holy Wisdom), on Yerebatan Caddesi, was the largest cathedral in the world for more than 1,000 years, famed for its magnificent dome and stunning mosaics and frescoes. In its nearly 1,500-year history, it's served as a patriarchal basilica and a mosque, but today it's a museum of Byzantine art and architecture, of which it's the world's finest example. Admission is 10YTL ($6.65). Closed Monday.

The Blue Mosque (aka Sultan Ahmet Camii), on Sultanahmet Square, is the other great feature of the Istanbul skyline, with its multiple domes and six thin minarets. Built between 1609 and 1617 by Sultan Ahmet I, it was intended to rival the Ayasofya and was built on a design that relies on successively descending domes to create a large covered interior space. The overall effect is one of great harmony, grace, and power. Admission is free. Guests must leave their shoes at the entrance. The mosque is closed to tourists during prayer times.

In front of the Blue Mosque, the Hippodrome park was once the site of great chariot races and a center of Byzantine civic life. What remains from those times are three tall monuments, including the Obelisk of Tutmosis III, a 60-ton granite spike dating to the 13th century B.C. and brought here from the Egypt's Temple of Luxor around A.D. 390.

Diagonally across from the Ayasofya, on Yerebatan Caddesi, the Yerebatan Cistern is a vast underground reservoir built by the emperors Constantine and Justinian in the 6th century A.D., using 336 marble columns recycled from nearby Hellenistic ruins. Abandoned from the mid-15th century until its reopening in 1987, it's a stunning sight, with ancient decorative carvings on the columns, vaulted ceilings overhead, and goldfish swimming in the water below. Visitors can walk among the columns via a boardwalk. Admission is 10YTL ($6.65). Closed Tuesday.

Behind Ayasofya, Topkapi Palace, at the end of Babuhümayun Caddesi, served as the residence of sultans and administrative seat of the Ottoman Empire from the 15th century to the mid-19th century. Today the huge complex is a treasure trove of art and history that includes everything from holy relics (a piece of St. John the Baptist's skull) to sexy legend (the harem, which at its peak was home to more than 800 concubines). In summer it's wise to get a ticket to the separate harem tour after arriving at the palace; tours are conducted every half-hour. Admission to the palace is 20YTL ($13.30); the guided harem tour costs an additional 10YTL ($6.65). Closed Tuesday.