After the National Archaeological Museum of Athens, grab the metro at Omonia and take line 2 (red) two stops to Syntagma, where you can visit Syntagma Square in the Greek Parliament and the Tomb of the Unknown Soldier.

The draw of this square is the hourly changing of the guard ceremony. The guards, Evzones, wear the traditional kilts, red hat, white stockings, and shoes with pompoms, called tsarouhi.
You can even take a picture with one of the guards, but don’t try to make any funny poses or you will be reprimanded. The ceremonial changing of the guard occurs on Sundays at 11:00.

---