This Asian-inspired tower in a lush urban park provides spectacular panoramic views of Baltimore.

An astounding collection of medical specimens, including bits of President Lincoln.

A wonderland of caves in eastern Iowa.

An underground wonderland in Iowa.

Chilly air billows out from the entrance of an abandoned mine on a steep hillside, providing a refuge for Ice Age fauna and flora.

Piled high inside this warehouse and coffee shop are salvaged goods that span every corner of the globe.

For just a few bucks, this Iowa funicular will let you feel like an 1800s fat cat.

This zombie-themed restaurant stands out in the heart of corn country.

A warning to the weak-kneed: This narrow bridge does its swinging eight stories high.

If astronomy had a ghost, it would look like this observatory.

A herd of roughly 250 American bison roam these plains.

This shop is named for a runaway elephant who smashed through its doors, stole some peanuts, and spent five days on the lam.

More than 3,200 cookie jars line the walls and shelves of this little shop and over 1,000 salt and pepper shakers

Lions and tigers and leopards, servals, pumas, bobcats, lynxes, and ocelots... oh my!

A turn-of-the-century architectural marvel built on healing mineral springs and salt licks.

The site of a 19th century "dream city" that almost rivaled Chicago before being swallowed by the Indiana sand dunes.

A medical facility that has been kept frozen in time.

The longest navigable underground river in the United States is home to countless blind and albino animals.

A hidden network of subterranean passageways lies tangled beneath Indianapolis' bustling City Market.

World War II-era bunkers are hidden under the beaches of this picturesque park, which is still scattered with wartime watchtowers.

This splendid Versailles-inspired mansion has the largest French-style formal gardens in North America.

Enchanting gardens surround a derelict mansion, all hidden in plain sight behind a stone wall.

Once the supplier for noteworthy projects like the National Cathedral, this old brickworks now lies abandoned.

A rare example of a rural school in Washington, D.C.