The Valdivia expedition was a scientific exedition to explore the Deep sea. It was a German expedition, done in 1898 and 1899. A ship was bought from "Hamburg-Amerikanischen Packetfahrt-Actien-Gesellschaft" HAPAG and given instruments to be able to perform scientific measurements. The ship left Hamburg on 31st July 1898 and returned on 1st May 1899. The ship had travelled over 32.000 nautical miles. The expedition was very successful. The results were published in 24 volumes; publishing them took until 1940.