Built on a steep hill in the middle of a busy market area, the Rüstem Paşa mosque is yet another masterpiece from the ubiquitous master architect Mimar Sinan. If you weren't carefully looking for the entrance, you would almost certainly miss it: just a narrow set of nondescript stairs leading up from the street. So ascending these steps and emerging into the mosque's spacious courtyard is quite a surprise.
Popularly known as the Blue Mosque thanks to the color of the Iznik tiles lining its walls, the Sultan Ahmed Mosque dominates Istanbul's skyline with six minarets. Completed in 1616, the mosque is still used for worship, but due to its grandeur and location, has become a popular tourist attraction.