In the Summer of 1991, Bishop Jim Murray, Msgr. George Michalek, Sr. Joan Meerschaert, and I had the privilege (and thrill!) to walk the top of the Mackinac Bridge. (Keep in mind, this was ten years before the attacks of September 2011--- access was very different back then!) The four of us met up with an employee of the Mackinac Bridge Authority who drove us to the north tower of the bridge. We parked in one of the two southbound lanes and turned on the van's emergency flashers to divert traffic. Then three of us (the employee plus two of us) entered a very small elevator inside the tower, and took a very slow ride to the top. There are no windows inside the elevator, and it is very cramped. If one were claustrophic, this would not be a pleasant experience! When the elevator stopped, the three of us walked into a rather dark (a few light bulbs) but totally sealed "waiting area" (not sure what this area is called officially). The employee then led the way as we climbed a steel ladder up about 10 feet to the next floor and through an open access hatch. Here we could stop to catch our breath if we wanted. A second ladder awaited us and another 10' climb. The employee unlocked an oval access hatch, and popped it open. Each of us climbed out onto the top walkway of the south tower. A incredible view! It took me a few minutes to feel comfortable even standing up, but eventually I felt totally at ease. There are railings on both sides of the walkway, each about 48" tall. You can look over the railings, straight down to the road surface some 330 feet below--- and another 200 feet to the water! (One would have to intentionally climb over a railing to be unsafe.) The employee soon left us there and returned to the other two in our party waiting at the road surface. Several minutes later, we were again a group of five, enjoying the spectacular view on a perfect, warm, sunny day. After awhile, one gets rather comfortable walking around. There are two large aviation lamps on each end of the walkway. A short, 10-step stairway allows access to the lamps. After asking permission to walk up those stairs, I found myself next to the aviation lamp. It is about 12" in diameter. A small rope is clipped to two safety cables used by bridge workers to walk down the massive bridge support cables. What a view!