How humans have left Earth
This cool graphic shows the silhouettes, to scale, of the vessels humans have used to climb to space: spaceplanes (including three canceled ones), space stations (though Mir and Skylab are missing), and capsules. The ISS, as you'd expect, dominates the field on sheer size. One many readers may not recognize is Skylon, a British proposal to build a Single Stage to Orbit (SSTO) spaceplane. The designers think they have an engine design that overcomes the problem all previous designs have run into: that you can't carry enough fuel in any size ship to get the ship and cargo direct to orbit and back. Sadly, I don;t expect success here: their technology is immature, and I don't think their math will hold up when you get into the real world, where you constantly tweak the structure of a huge vessel for various stresses and needs until your margin is gone. But good luck, chaps!