Although the capital town is primarily beloved for its Venetian elegance and picturesque blind alleys, Naxos's most famous landmark is ancient: the Portara, a massive doorway that leads to nowhere. The Portara stands on the islet of Palatia, which was once a hill (since antiquity the Mediterranean has risen quite a bit) and in the 3rd millennium BC was the acropolis for a nearby Cycladic settlement. The Portara, an entrance to an unfinished Temple of Apollo that faces exactly toward Delos, Apollo's birthplace, was begun about 530 BC by the tyrant Lygdamis, who said he would make Naxos's buildings the highest and most glorious in Greece. He was overthrown in 506 BC, and the temple was never completed; by the 5th and 6th centuries AD it had been converted into a church; and under Venetian and Turkish rule it was slowly dismembered, so the marble could be used to build the castle. The gate, built with four blocks of marble, each 16 feet long and weighing 20 tons, was so large it
couldn't be demolished, so it remains today, along with the temple floor. Palatia itself has come to be associated with the tragic myth of Ariadne, princess of Crete.
Ariadne, daughter of Crete's King Minos, helped Theseus thread the labyrinth of Knossos and slay the monstrous Minotaur. In exchange, he promised to marry her. Sailing for Athens, the couple stopped in Naxos, where Theseus abandoned her. Jilted Ariadne's curse made Theseus forget to change the ship's sails from black to white, and so his grieving father Aegeus, believing his son dead, plunged into the Aegean. Seeing Ariadne's tears, smitten Dionysus descended in a leopard-drawn chariot to marry her, and set her bridal wreath, the Corona Borealis, in the sky, an eternal token of his love.
The myth inspired one of Titian's best-known paintings, as well as Strauss's opera Ariadne auf Naxos.
North of Palatia, underwater remains of Cycladic buildings are strewn along an area called Grotta. Here are a series of large worked stones, the remains of the waterfront quayside mole, and a few steps that locals say go to a tunnel leading to the islet of Palatia; these remains are Cycladic (before 2000 BC).