A grove of colossal man-made flowers built to collect the sun's rays.

Visitors can walk over the largest concentration of Columbian mammoths to have died from one event.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

Architectural monsters are devouring this palace's every door and window.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

A forgotten "city of water" underneath the famous Trevi district.

A monumental fountain in Rome features a large statue of Moses that has been criticized for centuries.

This California tree is the single source of the state's entire orange industry.

This marker identifies the location where three states converge.

This 41,000-acre wetland complex is the largest marsh in the interior of the United States.

This geometric feat is a testament to the Incas' mesmerizing architectural abilities.

A monument dedicated to a local softball team full of clowns.

Once a dining hall for boarding school students, this lodge was a popular haunt for nuclear physicists working on the Manhattan Project.

This museum started as a collection of Manhattan Projects and continues to add exhibits as they are declassified.

These strange carved boulders in a forested canyon resemble tiny stone villages.

St. Augustine's record-setting narrow street was designed to protect against pirates.

Bronze footprints mark the path where a civil rights leader tried to march in peaceful protest before being knocked unconscious.

Location of a reliquary containing bone fragments of 18 saints.

An icon among Florida's pre-Disney tourist attractions.

Dubbed the "smallest church in America," this tiny sanctuary was a local grocer's dream come true.

Discovered by a soldier during the Revolutionary War, these springs helped create an iconic South Carolina ginger ale.

The highest point in South Carolina was once owned by an energy company that neglected it but now the state is taking it back.

The highest point in Iowa, while not that impressive to mountain states, has earned its own monuments.