Isthmus in the context of "Nesebar"

The Isthmus of Corinth (Greek: Ισθμός της Κορίνθου) is the narrow land bridge which connects the Peloponnese peninsula with the rest of the mainland of Greece, near the city of Corinth. The 6.3 km (3.9 mi) wide Isthmus was known in the ancient world as the landmark separating the Peloponnese from mainland Greece. In the first century AD the geographer Strabo noted a stele on the Isthmus of Corinth, which bore two inscriptions. One towards the East, i.e. towards Megara, reading: "Here is not Peloponnesus, but Ionia" (τάδ᾽ οὐχὶ Πελοπόννησος, ἀλλ᾽ Ἰωνία) and the one towards the West, i.e. towards the Peloponnese: "Here is Peloponnesus, not Ionia" (τάδ᾽ ἐστὶ Πελοπόννησος, οὐκ Ἰωνία); Plutarch ascribed the erection of the stele to the Attic hero Theseus, on his way to Athens.

To the west of the Isthmus is the Gulf of Corinth, and to the east the Saronic Gulf. Since 1893 the Corinth Canal has run through the isthmus, effectively making the Peloponnese an island. Today, two road bridges, two railway bridges and two submersible bridges at both ends of the canal connect the mainland side of the isthmus with the Peloponnese side. Also a military emergency bridge is located at the west end of the canal.

Peñón de Vélez de la Gomera (Spanish pronunciation: [peˈɲon de ˈβeleθ ðe la ɣoˈmeɾa]), also known as Hajar Badis (Arabic: حجر بديس, romanized: Hajar Badis), is a Spanish exclave and rocky tidal island in the western Mediterranean Sea. It is connected to the Moroccan shore by a sandy isthmus, and to a smaller islet to the east, La Isleta, by a rocky isthmus. The tidal island was historically named Hajar Badis (Rock of Badis), referring to its proximity to the town of Badis.

Vélez de la Gomera, along with La Isleta, is a historic overseas possession known as a plaza de soberanía. It is administered by the Spanish central government and has a population consisting only of a small number of Spanish military personnel.

In biogeography, a land bridge is an isthmus or wider land connection between otherwise separate areas, over which animals and plants are able to cross and colonize new lands. A land bridge can be created by marine regression, in which sea levels fall, exposing shallow, previously submerged sections of continental shelf; or when new land is created by plate tectonics; or occasionally when the sea floor rises due to post-glacial rebound after an ice age.

A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as a reef, a barrier island or islands, a barrier peninsula, or an isthmus. Lagoons are commonly divided into coastal lagoons (or barrier lagoons) and atoll lagoons. They have also been identified as occurring on mixed-sand and gravel coastlines. There is an overlap between bodies of water classified as coastal lagoons and bodies of water classified as estuaries. Lagoons are common coastal features around many parts of the world.

The Lake Prespa is located on the tripoint of North Macedonia, Albania and Greece. It is a system of two lakes separated by an isthmus: the Great Prespa Lake, divided between the three countries, and the Little Prespa Lake, mostly within Greece. They are the highest tectonic lakes in the Balkans, at an elevation of 853 metres (2,799 ft).

The area contains three national parks: Galičica National Park in North Macedonia, Prespa National Park in Albania, and Prespa National Park in Greece. The largest town in the region is Resen in North Macedonia. In 2014, Ohrid-Prespa Transboundary Biosphere Reserve between Albania and North Macedonia was added to UNESCO's World Network of Biosphere Reserves.

Gyali (Greek: Γυαλί "glass", also spelled Giali or Yali, pronounced [ʝaˈli]) is a Greek volcanic island in the Dodecanese, located halfway between the south coast of Kos (Kardamaina) and Nisyros. It consists of rhyolitic obsidian lava domes and pumice deposits (which are mined in huge quantities). No historical eruptions are known, but the most recent pumice eruptions overlie soils containing pottery and obsidian artifacts from the Neolithic period (10,000–4,500 BC). The island has two distinct segments, with the northeastern part almost entirely made of obsidian and the southwestern part of pumice. These are connected by a narrow isthmus and beach made of modern reef sediments. Anciently, the island was known as Istros (Ancient Greek: Ἴστρος).

Jan Mayen (Urban East Norwegian: [jɑn ˈmɑ̀ɪən]) is a Norwegian volcanic island in the Arctic Ocean with no permanent population. It is 55 km (34 mi) long (southwest-northeast) and 377 km (146 sq mi) in area, partly covered by glaciers (an area of 114.2 km (44.1 sq mi) around the Beerenberg volcano). It has two parts: larger northeast Nord-Jan and smaller Sør-Jan, linked by a 2.5 km (1.6 mi) wide isthmus. It lies 600 km (370 mi) northeast of Iceland (495 km [305 mi] NE of Kolbeinsey), 500 km (310 mi) east of central Greenland, and 900 km (560 mi) northwest of Vesterålen, Norway.

The island is mountainous, the highest summit being the Beerenberg volcano in the north. The isthmus is the location of the two largest lakes of the island, Sørlaguna (South Lagoon) and Nordlaguna (North Lagoon). A third lake is called Ullerenglaguna (Ullereng Lagoon). Jan Mayen was formed by the Jan Mayen hotspot and is defined by geologists as a microcontinent.