Grand Lake was created by a depression era project that remains the longest of its kind in the world.
News on 6 reporter Rick Wells flew with SkyNews 6 to Grand Lake to tour the Pensacola Dam.
The Pensacola Dam on the south end of Grand Lake is the longest multiple arch dam in the world. You can see the arches from the air, 51 of them stretching for almost a mile holding back all of Grand Lake.
GRDA tour guide Forrest Graham: "the Romans developed the arch principal." That allows a relatively thin barrier, in this case only four feet thick, to maintain enormous strength. "Four feet of concrete shaped this way and hold back that much water."
Built during the Depression, when labor was plentiful and materials were in short supply the arch design was perfect for the project.
It was the first hydroelectric project in Oklahoma. There are six generators located 11 stories below the top of the dam. Water from the lake turns gigantic turbines, which generates the electricity.
Part of the dam was a designated shelter in case of nuclear attack. There are dimly lit hallways with stuff seeping through the concrete walls. Not a problem I was told.
70 years ago, 3,000 men built an engineering marvel that provides flood control, a huge recreation area and some electricity too.
Tours of the dam are available seven days a week from May through Labor Day. The tour last approximately one hour and it is free.