Ever notice how big Greenland is on most maps? There is a problem with flat maps. Due to the distortion that happens when you plaster a sphere onto a flat surface, the sizes of things at the top and bottom tend to get all wonky.

Globes offer a much more accurate view of the world, but even they are not perfect. When you look at the sphere, its curvature distorts relative size because the countries curve away from you. If you want the best view of what our world really looks like, there is only one place for you: standing in the center of the Mapparium.

In the Mary Baker Eddy Library in Boston, Massachusetts is a three-story stained glass globe, flipped inside-out so the left-right orientation is correct. A 30-foot-long glass bridge runs straight through the globe. Standing in the center of those 608 stained glass panels, you can see the inside-out world in perfect scale. And It. Is. Weird!

It is fascinating to view Earth this way. Africa is huge. North America, Europe, and Asia are all jammed way up against the North Pole. You have to look nearly straight up to see them. Sizes and locations of continents and countries you’ve always taken for granted are suddenly unfamiliar.

The Mapparium was completed in 1935, meaning that while the relative size of its land masses is correct, some of the country names and boundaries are decidedly out of date.

In 1930, Boston architect Chester Lindsay Churchill was commissioned to design the new Christian Science Publishing Society headquarters to compete with the other grand newspaper headquarters of the day. He had seen the 12-foot globe in the lobby of the New York Daily News building and wanted to do one better.

Originally called “the Glass Room” or “the Globe Room,” the Mapparium gets its name from the Latin words mappa (“map”) and arium (“a place for”). Built by Old World craftsmen who were fleeing an emergent Nazi Germany, the Mapparium opened to the public May 31, 1935. It cost $35,000—which was a lot of money back then.

Based upon Rand McNally political maps published in 1934, the Mapparium put the politics of the era on view. Colonialism was still in full effect, with huge swathes of Africa divided among the European powers. Much of Southeast Asia is still French Indochina and don’t go looking for Israel or Pakistan, as they didn’t exist yet. Some countries are there but with their earlier names like Siam or Persia. Germany looms ominously large.

Renovated in 1998 and lit from the outside with LEDs the Aapparium is now able to put on a short light and sound show. To clean the interior of the three-story glass globe workers have to use a cherry-picker that is set up in the middle of the bridge. Workers go out on the machine’s arm and clean each panel with a gentle solution.

The Mapparium also has another unusual quality, one that was almost certainly unintentional. Like the dome in Grand Central it is a whispering gallery, but being a sphere, its acoustics are even stranger. People whispering privately in India can be heard quite clearly in Mexico. And if you stand in the center, you will find yourself speaking to yourself in surround sound.