Hidden in plain sight on a pair of Manhattan subway tunnels are a pair of public instruments that sing to each other.

A huge musical instrument played by the ocean.

Finale of "William Tell Overture" can be heard as drivers pass over grooves in the road.

The Mighty Wurlitzer organ continues to belt out the tunes at downtown El Segundo's historic home for silent and classic movies.

A metal tree emits eerie, melodic notes on top of Lancashire's Crown Point.

Three floors of musical instruments coming from all corners of the world and hundreds of years of musical history.

This sculpture is an instrument played by the swell of the seas.

The massive, incredibly rare instrument is over 11 feet tall with a range so deep it goes lower than humans can hear.

This nine-story building can be played like an instrument.

A large instrument played by the wind.

A Seussian sculpture made of brass instruments.

When the rain falls, this drain system turns into a musical instrument.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

A whimsical sensor instrument for Minneapolitans to play on their walks to work.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

The fountain marks the area where hundreds of accused witches were burned at the stake.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.

Carved faces add a touch of magic to this island's impressive oak trees.

A wacky, UFO-shaped house in a suburban neighborhood.

"The Donut" was built as part of an expensive, ill-fated engineering endeavor.

The walls are decorated with whimsical murals painted by the creator of the Madeline franchise.

This Croatian computer club features such gaming relics as the infamous Virtual Boy and an 8-bit Pacman machine.

One of its engravings is believed to be among the first representations of medical and surgical instruments.

The oldest surviving botanic garden in the United States.