The world-record holder for the longest bridge stretching continuously over water.

On Waikīkī Beach, a monument to four extraordinary individuals of dual male and female spirits who brought the healing arts from Tahiti to Hawai'i.

The only royal palace on U.S. soil has been a territorial capitol, a military headquarters, and a prison for a queen.

A museum dedicated to the history and exploration of both popular music and science fiction.

This massive chalk hill carving is one of England's most beloved giant horse geoglyphs.

Frank Lloyd Wright died a year before construction on his largest public project even began.

George Lucas donated this park to honor the birthplace of his two biggest movie franchises.

A massive ultra-modern church presents a science-fiction view of Catholicism's inclusive future.

The sea once considered an ecological wasteland is now called "crown jewel of avian biodiversity" by scientists.

Erroneously called the world's tallest flagpole, this landmark is devoted to "good neighborliness."

A hand-built folk art installation covered with messages of God's love.

Burping, gurgling geothermal mud pots by the Salton Sea.

The ghostly remains of an accidental sea.

Believed to be the only Orthodox church in the world that features a free-standing pulpit.

The hallucinogenic center of the ancient world.

Monasteries on rock pillars, once accessible only by frayed ropes.

The only surviving choragic monument is a trophy awarded in 334 BC for the winning dramatic chorus.

Legend says this sacred tree was a gift from goddess Athena.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

An ancient octagonal weather station named for the eight Greek gods of wind.

This mystical orb covered in strange symbols is thought to have been used in ancient Greek magical rituals.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

A 2,000-year-old computer demonstrates remarkable engineering and astronomical precision.

These Great Lakes sea caves accessible by boat in the summer turn into temples of ice reachable by foot in the winter.