Facing Aya Sofya across a small park and mirroring its domed silhouette, the early 17th-century Blue Mosque is one of only a handful of mosques in the world to boast six minarets. Is it really blue? Well, not noticeably, although all the walls are papered with fine İznik tiles. To view it as the architect, Sedefkar Mehmed Aga, originally intended, enter via what looks like the side entrance from the Hippodrome. Afterwards, pop your head into a building the size of a small mosque on the corner of the complex. This houses the tomb of Sultan Ahmed I, the man who gave his name to both the mosque and the neighbourhood.
Open: Open everyday, outside prayer times
Entrance Fee: No entrance fee