This long unused shot tower on the Mississippi remains a point of pride for a small city in Iowa.

The high point on the 16th president's eponymous roadway is marked by a massive version of his head.

A monument to the egos of two railroad magnates that fell into decline along with their careers.

Miraculous tree that seems to sprout out of solid rock.

This sky-high radio mast is formerly the tallest man-made structure in the world.

The mayor made the declaration in 2004.

The lowest point in South Dakota and the source of the Minnesota River.

Derelict buildings are all that remain of a complex at the site of one of the worst mining disasters in Montana history.

One of Savannah's oldest and most haunted cemeteries, featuring graves desecrated by Sherman's Union Army.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

The spot in the Mile-High City that's exactly 5,280 feet above sea level (at least for now).

WWI hospital ship lost in a cyclone turns up on the coast of Fraser Island, where she remains rusted and forgotten.

This massive roadside mascot was the first version of the giant to illustrate his butt.

The world's longest known cave system.

The hotel where Martin Luther King Jr. was shot is now a museum dedicated to his work.

A bizarre roadside attraction and the first instance of miniature golf in the world.

Equal parts record-breaking temple to consumerism and bizarre fun park, it's more than you think it is...

3/4-scale model of the White House in Atlanta, Georgia.

This abstract roadside poultry was saved from demolition by outraged drivers and pilots.

Healing Springs that once ran red with soldiers' blood.

After just one epic test blast, this literal loose cannon proved too explosive for combat.

If all members were present at the table, a sixth of the world's wealth would be under the same roof.

Constant erosion has created a surreal landscape of bleached and preserved fallen trees.

Ruins of a Carnegie family mansion on Cumberland Island.