Before there was 4D, there was The Mapparium.
Picture a giant, hollow ball made of glass, completely indoors, surrounded by lights, and skewered through its middle by a footbridge made of glass. Stain the inside of the glass ball as if it were a political map of the Earth turned inside-out. This is The Mapparium, a low-tech experiment in optical overload that no one would have the time or money to build any more.
The Mapparium is sheltered inside the Mary Baker Eddy Library, next to the Christian Science Monitor HQ. It was built by Old World craftsmen who had fled Nazi Germany. As such, the political boundaries are frozen circa 1935, which can be a little disconcerting when you look for Israel or Vietnam.
The bronze framework of the mighty globe holds over 600 concave glass panels, which are illuminated by 300 lights placed outside. Electric clocks ring the equator, giving comparative times around the world. Visitors enter on the elevated bridge through the Indian Ocean and exit through the South Pacific. Acoustics are weird; people whispering privately near Australia can be heard distinctly in Greenland.
Why was this thing built? The tour guide gives a laconic, Down East explanation. "By standing on the crystal bridge, one sees our planet from pole to pole with none of the distortion of area and distance that occur on a flat map."
In 2002, The Mapparium opened to the public after four years of renovation. The glass sphere was augmented with a computer-controlled light show and sophisticated sound system (the acoustic design was tricky due to the unique reflective qualities of the 608 curved glass panels). Visitors are treated to a 6-minute audiovisual presentation while they stand on the bridge crossing the Mapparium's center.
Purists were happy to note that the globe's geography was NOT been updated. It still represents the pre-World War II, colonial countries of 1935, when it was designed by Boston architect Chester Lindsay Churchill.