A castle hand-built by a Spanish dreamer in the Australian tropical jungle.

This gracefully curving formation looks like a massive wave that was suddenly turned to stone.

A massive stairway that almost wasn't leads to one of Australia's most scenic vistas.

Woven tree art gives this towering Australian woodland a touch of mystical whimsy.

An abandoned railroad tunnel is now filled with bioluminescent bugs.

This dramatic sea spire is home to the world's rarest insect and is part of the lost continent of Zealandia.

Once the path of a railway tunnel, now home to thousands of glowing insects.

An Australian lake whose pink hue defies scientific explanation.

The UFO capital of Australia is the outback’s answer to Roswell.

The enormous isokinetic structure hangs within a science center in Estonia.

This little gem in the Gulf of Riga has a very rich heritage and distinct culture.

This old and disused water tower has received a new life as an art gallery with a piano staircase.

An abandoned textile factory on the "island of crows" was home to Estonia's first workers' strike.

Two old windmills got a new life as oversized sculptures of a man and a woman.

A wooden statue of an Estonian pagan god and King of the Setos stands atop a sacred hill.

This stoic bronze soldier stands as a symbol of Russian sacrifice or Soviet oppression, or maybe both.

A wooden replica of France's famous tower.

Historic slum of Tartu.

A historic scientific breakthrough that crosses nine borders.

Two well-hidden huts let animal lovers spend the night among the bears, wolves, and other predators of the forest.

First point in the Struve Geodetic Arc, a 19th century undertaking to measure the Earth's size and shape.

This dizzying tower was built to better broadcast the 1980 Moscow Olympics.

The Guardian of Tallinn.

Legend says lovers who hold hands while venturing along this stone jetty and kiss at the end will remain together forever.