A German design house managed to create concrete that'll let light pass through it by adding optical fibers to the mix. The optical fibers account for 4% of the translucent concrete formula, but it reportedly does not jeopardize the mixture's strength.

The concrete isn't entirely see-through like a pane of glass is, but it does allow enough light and color through to make things on the other side clearly distinguishable.

While we don't imagine governments will get to work knocking down old concrete structures to replace them using the new formula, it wouldn't hurt to give a little life to any heavy bunkerish-looking buildings in the future.

Translucent Concrete, via io9