UC3 Nautilus Largest Privately Built Submarine in the World

DEFENSE AND TECHNOLOGY -- UC3 Nautilus is a privately built Danish midget submarine. It was launched on 3 May 2008 in Copenhagen, Denmark. It was built over a three-year period as an art project by Peter Madsen and a group of volunteers, and cost approximately US$200,000 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.