A sea cave, also known as a littoral cave, is a type of cave formed primarily by the wave action of the sea. The primary process involved is erosion. Sea caves are found throughout the world, actively forming along present coastlines and as relict sea caves on former coastlines. Some of the largest wave-cut caves in the world are found on the coast of Norway, but are now 100 feet or more above present sea level. These would still be classified as littoral caves. By contrast, in places like Thailand's Phang Nga Bay, solutionally formed caves in limestone have been flooded by the rising sea and are now subject to littoral erosion, representing a new phase of their enlargement.

Some of the best-known sea caves are European. Fingal's Cave, on the Scottish island of Staffa, is a spacious cave some 70 m long, formed in columnar basalt. The Blue Grotto of Capri, although smaller, is famous for the apparent luminescent quality of its water, imparted by light passing through openings underwater. The Romans built a stairway in its rear and a now-collapsed tunnel to the surface. The Greek islands are also noted for the variety and beauty of their sea caves. Numerous sea caves have been surveyed in England, Scotland, and in France, particularly on the Normandy coast. The largest sea caves are found along the west coast of the United States, the Hawaiian islands, and the Shetland Islands.

A sea generally refers to a large body of salt water, but the term is used in other contexts as well. Most commonly, it means a large expanse of saline water connected with an ocean, and is commonly used as a synonym for ocean. It is also used sometimes to describe a large saline lake that lacks a natural outlet, such as the Caspian Sea.

Arctic (belonging to the Arctic Ocean) and Antarctic (Southern Ocean) seas, as well as some other seas freeze in winter. This occurs below the freezing point of pure water, at about -1.8 °C (28.8 °F). Frozen salt water becomes sea ice.

Humans navigated seas from antiquity. Ancient Egyptians and Phoenicians navigated the Mediterranean Sea and the Red Sea. Hannu was the first see explorer of whom there is any information. He sailed along the Red Sea and further to the Arabian Peninsula and the African Coast around 2750 BC. In the 1st millennium BC, Phoenicians and Greeks established colonies all over the Mediterranean, including its outlets like the Black Sea. The seas along the eastern and the southern Asian coast were used by Arabs and Chinese for navigation, and the North Sea and the Baltic Sea were known to Europeans in Roman times. Other seas were not used for navigation in the antiquity and were actually discovered.

A cave or cavern is a natural underground space large enough for a human to enter. The term applies to natural cavities some part of which is in total darkness. The word cave also refers to smaller spaces like rock shelters, sea caves, and grottos.

Speleology is the science of exploration and study of all aspects of caves and the environment which surrounds the caves. Exploring a cave for recreation or science may be called caving, potholing, or, in Canada and the United States, spelunking (see caving).

The formation and development of caves is known as speleogenesis. Caves are formed by various geologic processes. These may involve a combination of chemical processes, erosion from water, tectonic forces, microorganisms, pressure, atmospheric influences, and even digging.

Most caves are formed in limestone by dissolution.

Solutional caves are the most frequently occurring caves and such caves form in rock that is soluble, such as limestone, but can also form in other rocks, including chalk, dolomite, marble, salt, and gypsum. Rock is dissolved by natural acid in groundwater that seeps through bedding-planes, faults, joints and so on. Over geological epochs cracks expand to become caves or cave systems.

Vassilis Konstantinos "Basil" Poledouris (August 21, 1945 – November 8, 2006) was an American music composer who concentrated on the scores for films and television shows. Poledouris won the Emmy Award for Best Musical Score for work on part four of the TV miniseries Lonesome Dove in 1989. He is best known for scores such as Conan the Barbarian (1982), and RoboCop (1987).

Born in Kansas City, Missouri, Poledouris was a Greek-American. He credited two influences with guiding him towards music: the first was composer Miklós Rózsa; the second his own Greek Orthodox heritage. Poledouris was raised in the Church, and he used to sit in services enthralled with the choir's sound. At the age of seven, Poledouris began piano lessons, and after high school graduation, he enrolled at the University of Southern California to study both filmmaking and music. Several short films to which he contributed are still kept in the university's archives. At USC, Poledouris met movie directors John Milius and Randal Kleiser, with whom he would later collaborate as a music composer. In 1985, Poledouris wrote the music for the movie Flesh & Blood of Dutch director Paul Verhoeven, establishing another durable collaboration in films.

Nicholas Edward "Nick" Cave (born 22 September 1957) is an Australian musician, songwriter, author, screenwriter, composer and occasional film actor.

He is best known for his work as a frontman of the critically acclaimed rock band Nick Cave and the Bad Seeds, established in 1983, a group known for its eclectic influences and musical styles. Before that, he had fronted the group The Birthday Party in the early 1980s, a band renowned for its highly gothic, challenging lyrics and violent sound influenced by free jazz, blues, and post-punk. In 2006, he formed the garage rock band Grinderman that released its debut the following year. Cave's music is generally characterised by emotional intensity, a wide variety of influences and lyrical obsessions with religion, death, love and violence.

Upon Cave's induction into the ARIA Hall of Fame, ARIA Awards committee chairman Ed St John said, “Nick Cave has enjoyed—and continues to enjoy—one of the most extraordinary careers in the annals of popular music. He is an Australian artist like Sidney Nolan is an Australian artist—beyond comparison, beyond genre, beyond dispute."