An 18th-century Spanish watchtower made entirely of seashell and concrete.

The walls of America's oldest masonry fort famously "swallowed" cannonballs.

These Great Lakes sea caves accessible by boat in the summer turn into temples of ice reachable by foot in the winter.

The site of an ancient Mississippian settlement that appears to have flourished during the 10th to 13th centuries.

This titanic Catholic church in Chicago is also a refuge of the fictional cult-favorite wizard detective Harry Dresden.

This surprising gem is a world-class archeological museum hidden at the University of Chicago.

One of the oldest continually operating drinking establishments west of the Mississippi.

The first Russian Orthodox church in North America and an Alaskan landmark.

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

Legend says Dungeons and Dragons players can get their dice blessed at the creator of the game's memorial.

An independent bookstore and press with a large collection of local and English-language literature.

The first public library in the Americas has more than 45,000 books dating back to the 15th century.

One of Canada's most incredible rare book collections holds hundreds of thousands of gorgeous tomes that the general public can touch.

While this is positively the smallest library in Canada, it aspires to be the smallest in the world.

This tiny abode has been covered in the art of the little old lady who made her life and living there.

One of Canada's tiniest museums tackles the world's largest turtle.

A series of waterfalls so massive they straddle the border of Argentina and Brazil.

This tiny movie theater was the last one in the U.S. constructed in the Nuevo Deco architectural style.

Tokyo’s only Vaudeville-cuckoo clock–steampunk-Victorian curio cabinet time piece.

The premier place to experience the Victorian imagining of the steam-powered future.

A library of only unpublished manuscripts.

A one-ton statue of Steve Rogers beautifies the entry to a Brooklyn Bed, Bath & Beyond.

A Jenga-style cylindrical tower of books that appears to go on forever.

These mysterious ancient stone spheres were created by a civilization lost to time and are now mostly lawn ornaments.