These are the intake towers at Hoover Dam. Water is drawn in at the bottom and funneled down into the generators of the dam. There are four towers sitting in Lake Mead. Two sit on the Arizona side, and two on the Nevada side. On each of the two nearest towers are large clock faces. One clock reads Nevada time (Pacific Time Zone), the other reads Arizona time (Mountain Time Zone). For half the year the clocks are one hour apart. For the remainder of the year the clocks read the exact same time. Why? Because Arizona has voted not to observe Daylight Saving Time. Therefore, when the Pacific Time Zone begins Daylight Saving Time and Arizona does not change its clocks, it brings both the Arizona and Nevada clocks into synchronicity.