Thira (regional unit) in the context of "Ios (island)"

Santorini, officially Thira or Thera, is a Greek island in the southern Aegean Sea, about 200 km (120 mi) southeast from the mainland. It is the largest island of a small, circular archipelago formed by the Santorini caldera. It is the southernmost member of the Cyclades group of islands, with an area of approximately 73 km (28 sq mi) and a 2021 census population of 15,480. The municipality of Santorini includes the inhabited islands of Santorini and Therasia, and the uninhabited islands of Nea Kameni, Palaia Kameni, Aspronisi, Anydros, and Christiana. The total land area is 91 km (35 sq mi). Santorini is part of the Thira regional unit.

Santorini is the most active volcanic centre in the South Aegean Volcanic Arc. The volcanic arc is approximately 500 km (300 mi) long and 20 to 40 km (12 to 25 mi) wide. The region first became volcanically active around 3–4 million years ago, though volcanism on Thera began around 2 million years ago with the extrusion of dacitic lavas from vents around Akrotiri. One of the largest volcanic eruptions in recorded history struck the island about 3,600 years ago, leaving a large water-filled caldera surrounded by deep volcanic ash deposits.

Anafi or Anaphe (Greek: Ανάφη; Ancient Greek: Ἀνάφη) is a Greek island community in the Cyclades. In 2021, it had a population of 293. Its land area is 40.370 square kilometres (15.587 square miles). It lies east of the island of Thíra (Santorini). Anafi is part of the Thira regional unit.

Folegandros (also Pholegandros; Greek: Φολέγανδρος) is a small Greek island in the Aegean Sea that, together with Sikinos, Ios, Anafi and Santorini, forms the southern part of the Cyclades. Its surface area is 32.216 square kilometres (12.439 sq mi) and it has 719 inhabitants (2021).It has three small villages, Chora, Karavostasis, and Ano Meria, which are connected by a paved road. Folegandros is part of the Thira regional unit.

Sikinos (Greek: Σίκινος) is a Greek island and municipality in the Cyclades. It is located midway between the islands of Ios and Folegandros. Sikinos is part of the Thira regional unit.

It was known as Oenoe or Oinoe (Ancient Greek: Οἰνόη, Island of Wine) in Ancient Greece. It contrasts with nearby islands, such as Ios, in being quiet and relatively less developed. There are two villages, "Allopronia" on the south sea side, being the port, and another higher up in the hills being the chora. The chora up on the hills is composed of two settlements adjacent to each other, "Castro" to the west and "Chorio" to the east. There are a handful of tavernas in the chora and harbor. The beach at the harbor is one of two large sandy beaches on the island. Several ancient ruins rest on the island, although some are remote. There are three paved roads, one built to connect to the heliport and the other sandy beach, and there are several well-maintained dirt roads, and seven mapped footpaths. Much of the island is very difficult to access due to the terrain. Nearly all of the island's area is covered by terraces once used for extensive agriculture. Now only a handful are used across the island, most operating on government subsidies. The municipality had 253 inhabitants at the 2021 census. It includes the uninhabited island of Kardiotissa and other uninhabited islets. Its total land area is 42.507 square kilometres (16.412 sq mi).

Akrotiri (Greek: Ακρωτήρι) is a village and a community on the island of Santorini in Greece. It is located 15 kilometers south of the capital Fira, built on the slopes of a hill offering staggering views of the caldera cliffs. On top of this hill, there are remains of a Venetian castle (Goulas). Akrotiri is part of the Thira region and had 515 permanent inhabitants according to the Greek census of 2021.

Approximately 2 km southeast, the Minoan Bronze Age Akrotiri archaeological site is located. This is one of the most important of its kind in the Aegean.