With his eponymously named mosque, Sultan Ahmet I (r1603–17) set out to build a monument that would rival and even surpass the nearby Aya Sofya in grandeur and beauty. Today it's more widely known as the Blue Mosque.

The mosque's architect, Mehmet Ağa, managed to orchestrate the sort of visual wham-bam effect with the mosque's exterior that Aya Sofya achieved with its interior. Its curves are voluptuous, it has six minarets and the courtyard is the biggest of all of the Ottoman mosques. The interior has a similarly grand scale: the blue tiles that give the building its unofficial name number in the tens of thousands, there are 260 windows and the central prayer space is huge.

To best appreciate the mosque's design, enter the complex via the Hippodrome rather than from Sultanahmet Park. Once inside the courtyard, which is the same size as the mosque's interior, you'll appreciate the building's perfect proportions.

The mosque is such a popular attraction that admission is controlled so as to preserve its sacred atmosphere. Only worshippers are admitted through the main door; tourists must use the south door.

Inside, the stained-glass windows and İznik tiles lining the walls immediately attract attention. Although the windows are replacements, they still create the luminous effects of the originals, which came from Venice. You will also see immediately why the Blue Mosque, constructed between 1606 and 1616, more than a millennium after Aya Sofya, is not as daring as its venerable neighbour: four huge 'elephant's feet' pillars hold up the dome, a less elegant but sturdier solution to the problem of support.

The tile-encrusted Tomb of Sultan Ahmet I, the tomb of the Blue Mosque's great patron, is in a separate building on the north side facing Sultanahmet Park. Ahmet, who had ascended to the imperial throne aged 13, died one year after the mosque was constructed, aged only 27. He rests here with a dozen or so children (his decedents), powerful evidence that wealth and privilege didn't make the imperial family immune to tragedy.