The objective of underwater archaeology is to research, preserve, restore, study, evaluate and present the submerged archaeological wealth. This wealth consists of every kind of edifice, harbour works, cities, fortifications etc. – that due to geological alterations sank into the sea – as is also the case with commercial craft, warships or even mere fishing vessels that happened to sink along with their cargo. The cargo of the wrecked ship may consist of objects of everyday use – belonging to the passengers or the crew – tools, merchandise, (oil or wine amphorae, big jars with salted fish, architectural elements, sarcophagoi etc.) or even works of art transported from one place to another, a case common to the Roman period. This explains, to a certain degree, the great number of works of art found in wrecks that embellish Greek and foreign museums (the Ephoebos from Antikythera Island, the Poseidon from Cape Artemision, the Jockey, the bronzes of Riace, Italy, the Ephoebos of the Getty Museum, USA etc.). Underwater archaeology is an especially difficult field, since the scientists and specialists engaged have to operate not under common, normal conditions but deep down in the sea, which is quite a dangerous task. Athough the first international legislation protecting the submarine activities was introduced in Greece in 1834, it was never fully enforced.