This image features the main seating structure and the fountain at Churchill Downs, home of the most famous horse race in America, the Kentucky Derby. It was built in 1875 and the Derby has been run there since that year.

The description states:
CHURCHILL DOWNS
HOME OF THE KENTUCKY DERBY
LOUISVILLE, KENTUCKY
The beautiful grounds are open to visitors through the years. The world-famous Kentucky Derby take place annually on the first Saturday in May.
–The fastest Kentucky Derby run was by Secretariat in 1973, who also set records in the other two races of the Triple Crown, the Preakness Stakes and the Belmont Stakes. All three records remain unbroken as of this writing.
The postcard was used and is dated 3 April 1962.

This image features a colorized photo of Cumberland Falls, the most prominent feature of the larger Cumberland Falls State Resort Park.

The description states:
Glorious sunrises and colorful sunbows are common sights at Cumberland Falls, where on moonlit nights may also be seen the “moonbow,” an attraction shared only with Victoria Fall in Africa.
–This falls is sometimes compared to the larger and more famous Niagara Falls on the border of the United States and Canada. This postcard dates from the 1940s.

This image shows a tobacco farmer standing amidst large, healthy plants. This burley tobacco is most commonly grown in Kentucky for cigarette production.

The description states:
BURLEY TOBACCO FIELD
in Kentucky
This view shows a field of Burley tobacco that is almost mature and will soon be ripening for harvest. Tobacco is an important Cash crop for the Kentucky farmer.
–The errant capitalization is in the original. This postcard dates to the 1950s.
 

This image from Horse Cave, Kentucky demonstrates how long stalactites can grow when combined into a single mass and undisturbed.

The description states:
ONYX TAPESTRY, MAMMOTH ONYX CAVE, HORSE CAVE, KENTUCKY
The Only Tapestry depends between the cave chambers like a curtain shielding the entrancing scenes beyond, from the prying eyes of the visitor.
–The errant comma is in the original. This image is one that can easily be mistakenly viewed inverted, as lighting comes from below, which is not the expected direction. This card dates from the 1950s.

This image from Horse Cave, Kentucky, shows a formation made from many stalagmites combined into a single mass.

The description states:
MAMMOTH ONYC COLUMN
MAMMOTH ONYX CAVE, HORSE CAVE, KY.
This enormous mass of cave decoration rises as an onyx barrier through two elevations of the cavern passages, and is estimated to have required over ten millions of years to develop to its present proportions.
–Some of the color shown is natural, some is enhanced through the use of colored footlights. This card dates from the 1950s.

The location moves to another Kentucky cave, this one called Horse Cave, located in the town of the same name. This image is of a mass of stone which has formed from stalactites into a single object, and is not supported from below, thus the name Hanging Bridge.

The description states:
HANGING BRIDGE, MAMMOTH ONYX CAVE
HORSE CAVE, KENTUCKY
This is one f the most perfect of several large suspended masses of cave onyx unique in this Fairyland of KENTUCKY. Its weight exceeds 75 tons.
–This cave is located in the center of the town of the same name, and provided water, electrical power and natural air conditioning in years past. This card likely dates from the 1950s.

This image shows a tourist boat cruising through the waters of Echo River in Mammoth Cave.

The description states:
ECHO RIVER IN MAMMOTH CAVE
Mammoth Cave National Park, Kentucky
This famous cover stream is 360 feet beneath the surface. The subterranean boat ride is one of the outstanding attractions of Mammoth Cave. Eyeless Fish live in the waters of Echo River.
— The image is professionally lit, as there would not normally be a light in the middle of the boat illuminating the tourists’ faces. This image gives a very good idea of the size and type of boat commonly used in this era, the 1950s. It is being rowed by a National Park employee in uniform.

This image features formations in Mammoth Cave that resemble the columns built by the ancient Egyptians for the Great Hypostyle Hall at Karnak.

The description states:
RUINS OF KARNAK IN MAMMOTH CAVE
Mammoth Cave National Park, Kentucky
Erosive action of water has carved these massive limestone columns, which tower 80 feet above the cavern floor. The feature was named for the ancient Temple of Karnak on the Nile in Egypt.
— The people posing give a good sense of scale for the formations, which were not carved, but constructed by flowing water leaving mineral deposits over many millennia. The fashions visible indicate this card dates from the 1950s.
The blue lines on the card are from damage and wear.

This card features an image of the underground lake that is a waterway for tourists, as indicated by the long flat boats with seating shown at the bottom of the image.

The description states:
CRYSTAL LAKE IN MAMMOTH CAVE
Mammoth Cave National Park, Kentucky
The emerald green water of Crystal Lake provide a colorful contrast to golden tinted walls of the dome above the lake. Mammoth Cave is famous for its underground rivers and lakes.
— This card is one of the current series that dates from the 1950s.

This image features some sense of scale as provided by the tourists in the foreground and the stairway leading past the solid sheet of stone called The Falls.

The description states:
THE “FALLS” — FROZEN NIAGARA IN MAMMOTH CAVE
Mammoth Cave National Park, Ky.
Fluted stalactites form massive draperies, simulating a pipe organ at the “Foot of the Falls”
–The description of the formation varies unexpectedly from the typical waterfall to the pipes of a large organ, to drapes, so it seems there is a lack of consensus about how best to identify this feature. It is clear the cave bottom is far below where the viewers are standing.
The styles of clothing indicate the image dates from the 1950s.