Colorful promotional bird's-eye view of the Lake of the Ozarks, showing tourist points of interest, as well as the Bagnell Dam and its powerlines stretching out to St. Louis.
The view was issued by the Lake of the Ozarks Association to encourage tourism in the region. The verso features a plethora of advertisements for local businesses and interesting schematic strip map of lakeside resorts.
After its creation in 1931, the Lake of the Ozarks, as it was popularly called, became one of Missouri's most popular tourist destinations.
Wikipedia gives the following overview of the reservoir's history:
A hydro-electric power plant on the Osage River was first pursued by Kansas City developer Ralph Street in 1912. He put together the initial funding and began building roads, railroads, and infrastructure necessary to begin construction of the dam, with a plan to impound a much smaller lake. In the mid-1920s, Street’s funding dried up, and he abandoned the effort.
The lake was created by the construction of the 2,543-foot (775 m) long Bagnell Dam by the Union Electric Company of St. Louis, Missouri. The principal engineering firm was Stone and Webster. Construction began August 8, 1929, was completed in April 1931 and reached spillway elevation on May 20, 1931. During construction, the lake was referred to as Osage Reservoir or Lake Osage. The Missouri General Assembly officially named it Lake Benton after Senator Thomas Hart Benton. None of the names stuck, as it was popularly referred to by its location at the northern edge of the Ozarks. The electric generating station, however, is still referred to by the utility company as the "Osage Hydroelectric Plant." While some sources indicate that more than 20 towns, villages and settlements were permanently flooded to create the lake, subsequent research indicates that the actual number was closer to eight, while several other sites had been previously abandoned, were relocated to make way for the lake, or were on high enough ground that the creation of the lake didn't affect them.
At the time of construction, the Lake of the Ozarks was the largest man-made lake in the United States and one of the largest in the world. It was created to provide hydroelectric power for customers of Union Electric, but it quickly became a significant tourist destination for the Midwest. Most of its shoreline is privately owned, unlike many flood-control lakes in the region that were constructed by the U.S. Army Corps of Engineers. The relatively stable surface elevation has created ideal conditions for private development within a few feet of the shoreline. There are over 70,000 homes along the lake, many of which are vacation homes. Spectacular scenery characteristic of the Ozarks has also helped to transform the lake into a major resort area, and more than 5 million people visit annually.