Thanks to Ride A Pale Horse, I can pass along a very excellent video of a special historical exhibit. That of the one German Kreigsmarine Unterseeboot that was captured by they US Navy just before D-Day 6 June 1944. I present for your viewing enjoyment, the U-505 - one of only two surviving Type IXCs in existence. U-505 can be seen in Chicago, Ill.
The only other surviving Type IXC can be found in the United Kingdom. U-534 was the last U-boat sunk in WWII and miraculously the whole crew was able to escape before she went down. In 1993 she was raised from her watery resting place.
Alas it seems U-534 may not last longer in one piece since its current owners are planning to cut it in three sections. Here are the two petitions that can be signed to try and save this historical warship.
And if you are adventerous and want to dive on a sunken U-boat in about 45 meters of water, the U-260 can be found off the coast of Ireland. This nine minute video shows off in some spots the inner pressure structure of the submarine. Like the air intakes just behind the conning tower. Or the encrusted periscopes who's optics are still clear. Or cruise down the deck and see the stern with its frozen propellers.
Finally there is one more U-boat still in existence and this one can be found in Germany. The U-2540 is a Type XXI boat and was scuttled on 4 May 1945. Raised in 1957. Presently located in Bremerhaven and is open for tours.