My first minecraft world, includes:

*castle, with keep, towers,lava moat etc
*A wooden pirate ship with working cannons
*A large TNT Cannon
*~1/3 Scale Iowa Class battleship
*Massive monorail line "Skyway" which leads to
*Huge Watchtower/Fortress/Cathedral
*Also has a pyramid which houses some treasure
*Numerous mines which lead to the bedrock
*Argonath(LOTR) style statue
*Walled city(wip)
*Miles of underground tunnels
*Underground missile base, with working missile launch system

continually worked on since beta 1.2 or so

This a world war 2 battle ship with working lower set cannons (upper deck cannons are not usable.) The ship also has a bridge.