This image shows a portion of the legendary U.S. Highway 66 as it passes through a cut in the hills of the central Ozark Mountains in Missouri.
This photo post card has no description on the back.
The picture calls out the large cut in the hill for the highway to pass through on a consistent level, but also notes that this is a four lane section of the highway, which was rare at the time. Much of U.S. Highway 66 was two lanes for a considerably longer period, particularly in the remote areas of the west. When the U.S. Highway system was supplanted with the Interstate System, the four lane sections of 66 were often reused, while the two lane sections were either enlarged, as happened here, or abandoned for better roadbed and routes.
This image likely dates from the 1940s.

This image shows a tourist path through Stark Caverns, featuring the narrowed ceiling described as the Appian Arch. Presumably this is in reference to Roman arches along the Appian Way, an ancient Roman road.
There is no description on the back of this photo card. The woman in back is a common feature intended to give a sense of scale to an otherwise difficult to interpret scene. The path is obviously prepared and maintained for tourists.
This card likely dates from the 1940s.

This is an image from a time before the recent postings, this time in black and white, of a sheet like formation in Stark Caverns near Eldon, Missouri.
There is no description on the back of this card, as it is a photograph printed in postcard form with address and note markings on the back.
The ‘chandelier’ is the large formation centered in the picture, a complex formation made of multiple flows of water over limestone.
This card likely dates from the 1940s.