For all of recorded history, the way between these islands has been by boat, and it still is. Ferries reach every inhabited island, fast catamarans and lumbering car ferries threading routes that fan out mostly from Piraeus, the port of Athens. The schedules thin in winter and thicken in summer, and a Greek island holiday is built around them: you watch the weather, you book the crossing, you learn which islands link directly and which require backtracking through a hub. The major islands have airports, some taking direct flights from across Europe in high season, but even the air network bends to the same logic of fragmentation. To island-hop is to accept that the journey is part of the trip, that you will spend hours on a deck watching one rocky silhouette sink behind you as the next rises ahead.

At the very center of the Cyclades lies a small, arid, almost waterless island that no one is allowed to live on, and it was once the most sacred place in the Greek world. This is Delos, where myth held that the goddess Leto, fleeing the jealousy of Hera, came ashore to give birth to the twin gods Apollo and Artemis. The island that sheltered the birth of the god of light became a sanctuary drawing pilgrims from across Greece and, in time, a cosmopolitan trading port. Its ruins are extraordinary: temples, a terrace of marble lions, the mosaic floors of merchants' houses, layer upon layer from the third millennium BC to early Christian times. Today you visit Delos by day boat from neighboring Mykonos, and you must leave before nightfall, as the ancients decreed: no one is born and no one dies on the sacred island.

Because the islands differ so completely, the smart way to choose one is by what you want. For great beaches, the names recur: Mykonos, Naxos, Rhodes, and many more, their west coasts running to fine sand and clear water. For ancient ruins and museums, Delos and Rhodes lead, with Kos and Samos close behind. For harbor towns of real beauty, there is Chios, Hydra, Symi, and Naxos, where the waterfront is the heart of island life. For medieval walls and fortresses, Corfu and Rhodes. For nightlife, Ios, Mykonos, and Santorini. For walking, the quieter islands like Sifnos and Tilos. For the deepest religious history, Patmos and Tinos. The lists overlap and contradict, which is the point: ask three travelers for the best Greek island and you will get three answers, all correct.

A small puzzle confronts the island traveler. On most Greek islands the main town shares the island's name, so Naxos town sits on Naxos and Paros town on Paros. But locals often skip the name entirely and call their main settlement simply Hora, sometimes spelled Khora, which means "the place" or "the town." On Naxos, Hora means Naxos town; on Paros, Hora means Paros town. The same word points to a different place on every island, which captures something true about the whole archipelago. Each island is, to the people who live on it, the place, the center of a small and self-contained world ringed by sea. The whitewashed lanes of a Hora, climbing from the harbor toward a windmill or a fortress, are where that world is densest, and where a visitor feels it most.

Some islands earn their fame through sheer drama of landscape. Santorini is the most famous: what looks like an island is in fact the rim of a vast volcanic crater that erupted catastrophically in the Bronze Age and collapsed into the sea, leaving a ring of cliffs around a flooded caldera. Villages of white cubes spill down the cliff edge, and the sunsets over the water have made it a honeymoon byword the world over. Nisyros is another volcano, its crater floor still steaming and walkable. These violent geologies sit beside islands of quiet green and others of bare rock, and the contrast is the enduring pleasure of the Aegean: no two crossings deliver you to the same kind of place, even when the sea between them is the same impossible blue.