This photo shows the bottom segment of the lowest of the 5 locks at the Three Gorges Dam.  Again, it's difficult to capture on film due to the scale.  For comparison, that orange rectangle on the gray bridge in the lower center is an 18-wheel truck.  In front of the truck in the center of the bridge are two black dots -- those are people!  Just to the left of the truck is one of the immense hinged gray doors in the lock system.  It will take 2-3 hours for a ship to traverse the locks, but smaller ships will be able to (for a higher fare) traverse the dam using a special elevator in about 40 minutes.