Portugal’s highest lighthouse has one of the most impressive focal planes in the world.

The Roman Emperor's lost summer home and grotto full of enormous sculptures sit along the Italian seashore.

Bacteria and algae give the salty water its bubblegum hue.

The Renaissance-era courthouse is a relic from the fortified town's centuries of Venetian rule.

The beautiful, ornate weather station is the most popular geocache in Salzburg.

The Brutalist building harbors an unusual inverted dome that swoops down over its central sacred room.

The ruins of a megalithic monument sit right in the garden of a luxurious Maltese resort.

A well-restored ancient archaeology site gives a real feel for life during the Roman age.

Home to part of the world’s largest private collection of original manuscripts and documents.

Built over an abandoned train yard, this hidden gem is full of winding paths and offers gorgeous views of Sydney Harbour.

A stunning two-story timepiece within a medieval Brick Gothic church.

A sinkhole and now a swimming hole, too, full of dazzling turquoise water.

The widest waterfall in Europe is a natural wonder and one of the only places where fish are caught in the air.

This Manchester laundromat is hiding something.

The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

A firefighting museum housed in a historic station whose Lookout Tower watches over Melbourne.

An overlooked memorial honoring the local Washington residents who died in World War I.

The old fire station features a mural that has more to it than first meets the eye.

A friendly monster lurks outside the State Library Victoria.

A secluded art gallery hidden within the cellars beneath Tallinn’s medieval monastery.

Beautiful tiles decorate many of the town's surfaces and stand testimony to its glorious artistic history.

A 19th-century utopian religious society designed to align with the latitude of Jerusalem.

A massive mausoleum towers over the gravestones in a 19th-century Italian "model village."

A small gallery and shop dedicated to an ancient style of hand-printed textile.