Submerged structures: Human settlements, caves and wells

The remains of countless ancient buildings and settlements are now submerged under water. Some remains are testimony to subsiding soil, others to the results of earthquakes, flooding, landslides or erosion. Some buildings, however, such as today’s Kampongs in Malaysia, were originally built on the water.


While Atlantis remains a legend, ruins found in archaeological underwater sites the size of Pompeii have been discovered. Some are the remains of the first settlements in an area, while others were built during the apex of sophisticated ancient civilizations. More than 150 sunken cities and port structures are located on the shores of the Mediterranean alone.

Submerged Caves and Wells

Underwater cultural heritage also encompasses artefacts and traces of ancient human life preserved in flooded caves, which either have always been submerged or have been flooded by the rise of the sea.

Some examples of such sites include:

  • The French Cosquer Cave, with its entry at a depth of 37 meters under water, features unique prehistoric  paintings and engravings made between 27,000 and 19,000 years ago, when the entrance to the cave was not yet submerged. While the entry of the cave currently lies deep under water, its discovery having cost several human lives, the paintings themselves, found in the depth of the cave, are not submerged.
  • The submerged caves known as Cenotes in Mexico and the Dominican Republic. The Chichen Itza Cenote in Mexico, a karst cave tunneled into limestone by groundwater, numerous artefacts. The use of this cenote was exclusively sacrificial and ceremonial and remains of human sacrifices have been found in it. Some cenotes contain very old human remains, the oldest to have been discovered being the oldest human skeleton ever found in the Americas.

Submerged ruins include:

  • The remnants of the lighthouse and the Ptolemaic ("Cleopatra’s") palace in the bay of Alexandria;
  • The city of Pavlopetri, which is 5.000 years old;
  • Parts of the world heritage site at Mahabalipuram, India;
  • The site of Dwarka, India, featuring remains of an ancient port, temples and settlements;
  • Jamaica’s Port Royal, destroyed by an earthquake in 1692;
  • The remains of Santa Fe la Vieja in Argentina;
  • The Bulverket fortification in Gotland, Sweden – a medieval fortification in a lake, dating from 1130 AD.

Remains of prehistoric settlements

Some remnants of prehistoric settlements bear testimony to life some thousand years ago. The oldest artefacts date back approximately 300,000 years. Artefacts found at such sites include pottery, log boats and timber remains. Sites have been found for instance

  • In Denmark, where 20,000 remains of Stone Age settlements are estimated to be located off the coast, for instance in Tybrind Vig and Ronæs Skov in Gamborg Fjord
  • A submerged settlement from circa 5,700 BC, abandoned circa 5,200 BC in La Marmotta, Italy
  • The Black Sea still houses Mesolithic settlements that are 7,000 years old.

Remains of dwellings built on lakes and rivers

Many remains of dwellings constructed on small natural or artificial islands or on piles in the water (as is still the city of Venice), have been discovered. Examples include:

  • The remains of ancient settlements in the Zurich lake and Lake Constance
  • The crannogs of Ireland and Scotland
  • La Colletière, France, a medieval lake-side dwelling
  • The pile settlement in a river close to Pompeii, Italy

Venerated sites

Many traces of ancient water-related religious sites have also been discovered in underwater archaeological grounds. These include:


  • The remains of ancient holy lakes and channels in Florida and Greece
  • Sunken Maya temples in Guatemala
  • And a true Sea-henge, the sites Holme 1 and Holme 2, which have been discovered off the coast of the English county of Norfolk. The sites consist of periodically submerged timber circles with small split oak trunks forming a circular enclosure.

World Heritage under water - Prehistoric pile dwellings around the Alps

A serial property of 111 small individual sites encompassing the remains of prehistoric pile-dwelling (or stilt house) settlements in and around the Alps has been inscribed on the World Heritage List. The sites were built from around 5,000 to 500 B.C. on the edges of lakes, rivers or wetlands.


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