Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.

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

Romans decided this 16th-century "talking statue" was so ugly, they named it after a primate.

Rome's first modern graffito is all that is left of a peaceful protest from the 1970s.

A sculpture serving as an homage to Pope John Paul II.

This 15th-century cave complex is one of the very few monasteries to stay open throughout World War II and the Soviet regime.

The ruins of an Estonian prison are drowning in the quarry lake where the convicts were once forced to work.

This stunning limestone waterfall is the highest in Estonia.

The oldest museum in Russia is home to a fascinating collection of nearly two million anthropological artifacts and anatomical curiosities.

An abandoned 14th-century castle and prison complex on a small island in the Neva River.

The largest art park on the European continent.

The composer did some of his finest work in this country home, including "The Nutcracker."

This newly renovated Soviet-era outdoor exhibition center is bigger than the principality of Monaco.

An iconic Soviet statue of working-class people.

Moscow's imposing monument to the Space Age.

Museum celebrating the achievements of the Soviet space program.

Gargantuan home of Russian science.

Some Moscow residents once claimed the bizarre, contorted mass of metal on top of the building was used to manipulate minds.

This massive monument honors the first human in space.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

This 19th-century fountain's namesake animal isn't what you think it is.

Giant topiary dog once played a role in a terrorist bomb plot.

During the Soviet era, the spire of this longstanding church was used as a radio transmission tower.

A monument commemorating the 852 lives lost in the sinking of the MS Estonia.