This cannon dating to 1755 has stood guard at this suburban intersection since 1915.

Originally dubbed "Retirement" by the Navy Commodore who built it in 1780, this beautiful mansion is now the centerpiece of a suburban community park.

The only surviving 19th-century water-powered mill found in the Washington, D.C. area.

This twice-relocated "Usonian" home is among the smallest built by master architect Frank Lloyd Wright.

An unremarkable wooden wheel built into the side of one of Rome's oldest hospitals was part of a policy to reduce infant exposure.

This field of concrete was once an active defense site armed with nuclear warheads.

This building at the south end of the boardwalk was once home to the U.S. Life-Saving Service and the U.S. Coast Guard before being rescued itself.

The only remaining African American schoolhouse in northern Virginia is now a museum dedicated to formerly enslaved people.

The Italian revolutionary's legendary wife is portrayed on horseback waving a gun and holding her child in this memorial on the Janiculum.

The 72-foot giant escaped confinement in a large patch of mulch only to be reburied in the sandy shores of the Potomac River.

A 15th-century monumental Latin inscription on this house celebrates Lorenzo Manilio's love for Rome.

This church is known as "The Home Church of George Washington and George Mason."

A large replica of a monumental Roman inscription is located on the side of this museum.

Art Deco stylings conceal the true nature of this bridge.

One of ancient Etruria's most spectacular archaeological sites with impressive necropolises and rugged landscape.

This hydrochronometer was invented by a Dominican monk and is a prime feature in this garden.

This medieval church in Rome was almost destroyed following a terrorist attack in 1993.

This gallery commissioned by Cardinal Spada is known for its magnificent optical illusion.

This small church was constructed over the ruins of three temples dating to the Roman Republic.

A rare example of a medieval house in Rome adorned with a melancholic inscription.

An ancient Egyptian obelisk is now used to commemorate fallen Italian soldiers.

A popular legend claims that the famous pizza was invented at a restaurant in this alley.

According to local folklore, this Roman sepulcher was once a throne for the Devil.

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