One of Mexico's youngest major cities still holds on to this structure representing its short modern history.

A small collection of iguana-infested ruins hides amid Cancún's bustling hotel zone.

A well-worn trail through thick woods in northern Montgomery County leads to an old schoolhouse.

This suburban park recalls the history of a famous tavern. Despite the name, it's no ordinary place!

One of the last schoolhouses constructed in the early 20th-century still standing in Montgomery County.

An amazing example of Federal-period architecture, truly unique to this region of the state.

The ruins of an old mill lie in a small ravine along a hiking trail near Little Seneca Creek.

This abandoned Victorian-style house was built in 1884.

The only public school for Black children in the region from 1895-1936.

Dating to 1793, this is the oldest building in Poolesville.

Once the center of a thriving early Black community called Martinsburg.

The whole world in one water tank.

The hidden ruins of a mill that is linked to an attempt to assassinate the vice president of the United States.

One of only two sites in the United States containing the remains of Buddha.

Built in 1815, the stabilized ruins of the grist mill and sawmill are now gated, but interpretive displays on the features and functions of the mill preserve its history.

This ruined quarry once produced the distinctive red sandstone used for construction projects in Washington, D.C.

The oldest surviving one-room schoolhouse in Montgomery County, Maryland.

Using a massive antenna made up of five miles of wire, two scientists tuned into organic radio waves from the planet Jupiter.

This golfball sized platinum iridium cylinder is the official starting point for all national weight calibrations

The U.S. government built the million-pound stack of steel during the Space Race.

Tiny observatory made big contributions to the study of the Earth's motion.

This small cemetery remains hidden behind a recreation center.

Three abandoned missile silos are hiding in plain sight behind a suburban development in Maryland.

A massive white oak tree provides a beautiful canopy near a suburban shopping center and stood before the signing of the Constitution.