If you want a tranquil place to reflect, organize a visit to Church of Panagia Kapnikarea. This house of prayer offers a wonderful respite from the busy routine of life.
You're spoiled for sightseeing choice when staying in Athens City Centre. Church of Panagia Kapnikarea is a good place to begin here, but there are plenty of other worthwhile attractions to enjoy. Parthenon, Acropolis Museum, and Ancient Agora of Athens are close to the house of prayer and will fill in your day nicely.
