The largest of Denmark's seven mysterious round churches stands on an island in the Baltic Sea.

Down this Cracovian street resides a plaque with a stark message about the city's air pollution.

A strange aquarium with stuffed fish, and almost no water for them to swim in.

The medieval center of the Islamic world was also once the seat of Saladin's sultanate.

Standing atop 2nd-century Roman ruins, this church is one of the oldest and most iconic in Old Cairo.

This unassuming tree stump reportedly traces its roots to the famous pharaoh queen's reign.

In Egypt's expanding metro area, many of the neighbors are dead.

This ancient structure is widely thought to be the oldest intact pyramid in the world.

Known as the Sistine Chapel of Egypt, this tomb houses some of the most well-preserved paintings in Egypt.

These Egyptian statues have survived for 3,400 years and were an acoustic wonder of the ancient world.

An endless sea of white conical domes.

Ozymandias’ time-keeping temple.

An ancient instrument used to measure the waters of the Nile so Egyptian farmers would know whether to expect famine or flood.

These 18th-century paintings of Warsaw were used to reconstruct the city after World War II.

A bronze replica of an elm tree that honors the victims that perished in Pawaik Prison.

The majority of the highest mountain in Poland is actually located in a different country.

Gliwice Radio Tower, likely the tallest wooden structure in the world.

This picturesque castle in Poland has a rich history, including a legend that ties it to lost Incan treasures.

This 13th century Gothic brick castle is the largest in the world by surface area.

This uber-quaint Polish village is known for its habit of painting elaborate floral motifs on just about everything.

Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

This unique building in the main square stands out among the city's typically Baroque architecture.

The eclectic seaside sanctuary caters to a rather fowl crowd.

This spectacular dome managed to survive after being bombed in World War II, in an event known as the "Miracle of Mosta."