I'm no engineer, but according to the three engineers on this trip, the Falkirk Wheel is pretty impressive. Hugh, our guide, said we were the first group he's ever met that requested to see the wheel. So we're unique, I guess. The Falkirk Wheel is the only rotating boat lift in the world and replaced a series of 11 locks when it opened in 2002. It lifts and lowers boats 79 feet in roughly 15 minute cycles (the lock series, by comparison, took most of the day to navigate).

Side note: Falkirk is also known for having the largest horse sculptures in the world (at 98.5 feet), known as the Falkirk kelpies. The Falkirk Wheel has miniature versions of these.

After our wheel adventure, we returned to Edinburgh and ran into traffic. Since I was scheduled to get the keys to our rental and we had a 5:00 tour of Real Mary King's Close, this was a problem. At roughly 4:50, we arrived at the rental. Two of us hopped out and the others were driven to the tour. At 4:55, we left the rental and started quickly walking to the tour. At 4:59, we started running (not at all frantically) through the streets of Edinburgh and miraculously, we made it.

Mary King's Close is an underground street in Edinburgh. The street was once above ground, but when part of it was demolished and new constructions built on top, Mary King's Close went underground. During the 1600s, when people lived and worked here, the plague swept through and killed hundreds. So of course, it's haunted.