Still quoting from my Eyewitness Travel Guide:

The Blue Mosque, which takes its name from the mainly blue Iznik tilework decorating its interior, is one of the most famous religious buildings in the world. 

Sultan Ahmet I commissioned the mosque during a period of declining Ottoman fortunes, and it was built between 1609 and 1616 by Mehmet Ağa, the imperial architect.

There were a gazillion tourists lined up to get in here, but the queue moved quickly.

Minarets.

Spigots for Muslim ritual ablutions.  Foot washing.

Is that a pretty shot?  I guess so.

See?  A gazillion tourists.

Mesmeric designs employing flowing arabesques are painted onto the interior of the mosque's domes and semidomes. 

The windows which pierce the domes no longer have their original 17th century stained glass.

Pretty rugs, designed so everyone knows where to pray.

The outside.

Another ablution fountain.