Church of Panaghia Kapnikarea, Athens

Stading at the heart of modern-day Athens, right in the high-traffic shopping area of Ermou Street, this charming Byzantine church, believed to have been constructed around 1050, is one of the city's oldest. Following a common pattern among early Christian structures, it sits atop an ancient Greek temple dedicated to a deity, possibly Athena (the protector of Athens) or Demeter (goddess of the harvest).

When King Otto I of Greece enlisted the Bavarian architect Leo von Klenze to design the new city layout of Athens, there was a consideration to demolish the church. Fortunately, King Ludwig I of Bavaria, a prominent supporter of the arts in Europe, stepped in to safeguard its grandeur, and the fact that it appears somewhat out of place only enhances its charm.

Kapnikarea is now regarded as one of Athens' most significant churches, consisting of a complex of three sections. The primary church on the southern side is dedicated to the Virgin Mary, with a colonnaded porch dating back to the 12th century. The chapel in the northern section is dedicated to Agia Varvara (or Saint Barbara), while an exonarthex was added on the western side.

The church's exterior showcases a splendid mosaic from 1936 depicting the Virgin Mary holding Jesus, crafted by Greek mosaicist Elli Voila. Inside, the walls are adorned with paintings influenced by the Byzantine tradition, created by a hagiography school, while the paintings in the vaulted narthex and the exo-narthex date back to 1900, with the exact artist remaining unknown.

Note that the church's opening hours can be irregular, but if it happens to be open, it's certainly worth stopping by.