Okay. This is not a joke. (I find myself having to say that on an increasingly frequent basis for some reason.)

Somebody has done gone and created translucent concrete.

Excerpts from the story:

It used to be only Superman who could see through concrete walls, but an exhibit at the National Building Museum shows mere mortals can do it too.

Called “Liquid Stone,” the show features variations of translucent concrete, a newfangled version of the old construction standby that offers a combination of aesthetics and practicality.

The translucent blocks are made by mixing glass fibers into the combination of crushed stone, cement and water, varying a process that has been used for centuries to produce a versatile building material. The process was devised by Hungarian architect Aron Losonczi in 2001.

One of the first demonstrations was a sidewalk in Stockholm made of thin sheets of translucent concrete. It looks like an ordinary sidewalk by day but is illuminated at night by lights under it.

A company in Aachen, Germany, called LiTraCon for “light transmitting concrete,” makes translucent blocks and plans to have them market-ready this year.

“Think of illuminating subway stations with daylight,” he suggested in an e-mail. Or using the concrete for speed bumps and lighting them from below to make them more visible at night.

Inventor Thomas A. Edison had the idea of an all-concrete house almost a century ago. Though he worked on it for years and spent a lot of money, the idea never caught on.

“Liquid Stone” will be on view [at the National Building Museum in Washington] though Jan. 23. Admission is free.

If I lived on the right coast, I’d go see it! (And have my picture taken with it.)

Shoot! What will they think of next . . . transparent aluminum or something?