Dave Gorman recommends a visit to the Greenwich foot tunnel this Easter. I couldn't agree more. I remember going to Greenwich as a kid to see The Cutty Sark, and then being completely bowled over to find that there was also a tunnel which actually went under the river!! Not only that, but the tunnel was so long and straight, that from one end you could see the upward curvature at the other end, foreshortened so that it appeared to be a steep incline. It was like the curvature inside the orbiting space station with Leonard Rossiter in 2001: A Space Odyssey.
I remember walking through the tunnel with my Dad, wondering if the water was going to drip through from The Thames, and whether the incline at the far end would be too steep to climb.