Panagia Gorgoepikoos

Also called the Little Metropolis, this diminutive Byzantine church stands beside the far larger Metropolitan Cathedral of Athens. Dating to the 12th or 13th century, it is famed for its exterior walls, which are built from a patchwork of reused ancient and early Christian marble reliefs, including a fragment of a classical calendar frieze. The cruciform structure is topped by a small dome and measures only a few metres across, making it one of the tiniest cathedral-rank churches.