The Jelgava Palace holds one of the few burial places of governor’s dynasties that is open to the public.

This striking arch, one of the first architectural elements constructed in Prospect Park, was recently restored to its original glory.

This set of concrete chambers resonates according to different notes of octaves.

A cave dwelling that was started by the Celts, expanded by monks, and finished by knights.

A Gothic cathedral created from volcanic rocks.

Lyon, France is home to two remarkably preserved Roman theaters, one dating back to 15 BCE.

For hundreds of years, automatons moving to metallic music have been marking the passage of time.

Lyon's miniature version of the Eiffel Tower was built as a statement in support of French secularism.

This abandoned church in central Lyon is missing its front stairs.

Hundreds of hidden passageways weave through the old quarters of Lyon.

One of the longest wooden benches in the world snakes around Geneva's Treille Promenade.

With over 10,000 lights, this engineering marvel lights up the city after dark.

This small-town opera house has appeared much more in national culture and history than its charming setting might suggest.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

A gothic church spire sits atop this skyscraper, the tallest church in the world.

20,000 pieces in a Frank Gehry-designed building.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

Sleepy Minneapolis block beats Guinness Record for most churches on one city block.

A Building for Your (Former) Funerary Needs.

One of the world's premier laboratories for hydraulic engineering research takes full advantage of the water's power.

1887 era Russian Orthodox church in Minneapolis.

This iconic water tower and failed bandstand is open for panoramic views once a year.

A memorial in the Tiergarten is a reminder of the suffering inflicted on homosexuals by the Nazi regime.

If it hadn't been caught in time, a flaw in the design of this Manhattan skyscraper could have led to its collapse.