Very recently, for example, a dozen centuries-oldshipwrecks-some of them unusually well-preserved-were found in the baltic sea by a gas company building and underwater pipelin between Russia and Germany. The oldest wreck probably dates back to medieval times and could be up to 800 years old, while the others are likely to be from the 17th to 19th centuries.Swedish marine archaeology experts analysed pictures of the wrecks and determined that they cloud be of a high historical value.