Pick one category for the following text. The options are - company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work. UC3 Nautilus - UC3 Nautilus is a privately built Danish submarine. It was launched on 3 May 2008 in Copenhagen Denmark. It was built over a three-year period as an art/hobby project by Peter Madsen and a group of volunteers and cost approximately US$200000 to build (1.5 million DKK).This submarine was Peter Madsen's third submarine design and at the time of launch was the largest privately built submarine in the world.
The answer to this question is:
Mean Of Transportation