My head starts to spin when I think of all the places in Istanbul that anyone who is interested in history, culture, cuisine, or architecture should visit. There are literally hundreds of things on my list. Here are the first 3:

Şehzade Camii: This mosque complex was built by Süleyman the Magnificent for his son Prince Mehmet who died of smallpox in 1543. Süleyman was so devastated at the death of his son that he sat with the body for 3 days before allowing the funeral rituals to begin (today Prince Mehmet’s body lays in a mausoleum beside the mosque). Sinan, the greatest Ottoman architect, was commissioned to build a dedicatory mosque, a task he completed around 1548. It was his first monumental complex. The interior is wide open and topped by domes and semidomes propped up by tiny arched windows through which light filters. The decoration’s symmetry and simplicity, contrasted with the theme of multiplicity evoke for me Borromini’s designs for San Carlino and Sant’Ivo alla Sapienza in Rome. Open daily except during prayers.

Kariye Camii (also known as the St. Savior in Chora and the Kariye Müzesi, and the Chora Museum): Originally built in the 6th century and underwent a series of renovations during its history, most notably in the 14th century following an earthquake when hundreds of square meters of the church were paved in shimmering gold and glass mosaics. Though the building was converted into a mosque in the 16th century, much of the Byzantine mosaic and fresco has been recovered, providing a precious glimpse at the opulence and iconography of medieval Constantinople. Open Thurs-Tues 9:30AM-4:30PM , 15 TL.

Rüstem Paşa Camii: Built by Sinan in 1561 for Rüstem Paşa, Grand Vizer under Süleyman the Magnificent. It is one of the architect’s most celebrated small mosques and is nestled nicely into what has been a bazaar for well over 500 years (peer over the balcony near the entrance to see the second hand coat exchange in all its chaotic glory). The building is preceded by a porch supported by spolia, antique columns, and embellished with Iznik tiles.
The interior, too, is paved in these precious ceramics, only adding to the exalted opulence of this masterfully designed house of prayer. Open daily except during prayers.