Nature · Earth Science
The intricate handshake of land and sea
Where continents meet the ocean, the coastline frays into a rich vocabulary of shapes: peninsulas reaching out into the water, bays and gulfs biting inland, and narrow straits and isthmuses linking — or separating — great bodies of land and sea. These forms have shaped trade, migration and history for as long as people have sailed.
Coastal outlines are sculpted by tectonic movement, changing sea levels, erosion and deposition. Rising seas drown lowlands to leave headlands and bays; sinking land or rifting opens gulfs and straits; and resistant rock stands out as peninsulas while softer rock is worn back into sweeping bays.
A plan view of how peninsulas, bays, gulfs, straits and isthmuses fit together where land and sea interlock.
Land almost surrounded by water
A peninsula juts into the sea, joined to the mainland at just one edge. Their long coasts and command of sea routes have made many peninsulas cradles of maritime cultures.
The sea reaching into the land
A bay is a broad inlet where the sea curves into the land; a gulf is a larger version. Their sheltered waters have hosted many of the world’s greatest harbours and cities.
Narrow gateways between seas
A strait is a narrow passage of water connecting two seas. Controlling these chokepoints — like Gibraltar or Malacca — has decided the fate of empires and world trade.
Land bridges and pointing headlands
An isthmus is a slim neck of land joining two larger masses — famously cut by canals like Panama. A cape is a sharp headland thrusting into the sea, often a landmark for sailors.