The Portara is a single monumental marble doorway standing on a low peninsula jutting into the sea at the edge of Hora. It is all that remains of a 6th-century BC temple to Apollo that was begun but never completed. The gateway — two enormous upright marble blocks topped by a lintel, each piece weighing several tonnes — has stood here for 2,500 years, and it frames every sunset over the Aegean so perfectly that it is hard to believe the effect was not intentional.
Walk out along the causeway from the port (it takes about five minutes) and you arrive at what the islanders call the Palatia — the palace. Up close the scale registers differently than it does from the waterfront. The marble blocks dwarf everything around them, worn smooth by centuries of weather and the hands of visitors who have been stopping here since antiquity. There is almost no shelter on the peninsula, which means the wind, when it blows, comes at you from every direction. Bring something warm if you're here for sunset.
Sunset is, without question, the time to come. The bars and cafés along the waterfront facing the Portara fill from an hour before — people with drinks, people with cameras, people who just walked up and sat on the stone. The Portara turns amber and then deep orange as the light drops, with the sea behind it going purple. It is one of those sights that looks exactly like the postcard and is still overwhelming in person. Go for the sunset, stay after the crowds drift away, when the peninsula empties out and the doorway stands lit by the last light with the town glittering behind it.
The archaeological site is freely accessible at all hours. A small information board on the causeway explains the temple's history and the myths associated with the site.