🚨MISSING PERSON🚨: Officials are investigating the whereabouts of a woman after she disappeared from a popular viewing area at Grand Canyon National Park. Martha Overholser, 66, was last seen on Dec. 10 at Mather Point, which is located on the South Rim of the Grand Canyon. Her phone was located below the rim along Hermit Road at an overlook called The Abyss, which is located about 10 miles west of Mather Point, a Grand Canyon spokesperson told FOX Weather. Authorities believe Overholser may have walked west from the Mather Point area toward Bright Angel Lodge on Hermit Road or toward Hermits Rest, which is the most western point of the South Rim of the Grand Canyon. Overholser was traveling alone from Sault Ste. Marie, in northern Michigan, as part of a commercial bus tour, according to the spokesperson. The bus tour was one of several that operate in the area which bring tourists to the Grand Canyon for the day. Overholser is described as a white female, 5 feet, 2 inches tall a...