Seductively curvaceous and enhanced by a lovingly attended park in front, Sultanahmet Mosque is Islamic architecture at its sexiest. Commissioned by Sultan Ahmet I (1603-17) and built for him by Mehmet Aĸa, a student of the great Sinan, this was the last of Istanbul's magnificent imperial mosques, the final flourish before the rot set in. It provoked hostility at the time because of its six minarets - such a display was previously reserved only for the Prophet's mosque at Mecca - but they do make for a beautifully elegant silhouette, particularly gorgeous when floodlit at night.
By contrast, the interior is clumsy, marred by four immense pillars, disproportionately large for the fairly modest dome they support (especially when compared to the vast yet seemingly unsupported dome that caps Haghia Sophia). Most surfaces are covered by a mismatch of Iznik tiles: their colour gives the place its popular name, the Blue Mosque.
In the north-east corner of the surrounding park is the türbe or Tomb of Sultan Ahmet I. It also contains the cenotaphs of his wife and three of his sons, two of whom, Osman II and Murat IV, ruled in their turn, Ahmet being the sultan who abandoned the nasty Ottoman practice of strangling other potential heirs on the succession of the favoured son.