Dexia Tower

Standing 145 meters tall, encompassing 38 floors, Dexia Tower is the third tallest building in Brussels. It is situated in the middle of Mint Square and is visible from several major traffic arteries in the capital. It has a total of 6,000 windows, 4,200 of which are installed with an average of 12 LED light bulbs, totaling 72,000 bulbs. Commissioned by Dexia and designed by LAb[au], the installation is part of a series by LAb[au] called "Who's Afraid of RGB?" It forecast's the next day's weather using a code of colors and geometric patterns. It also uses colors to countdown the hours until midnight, and then gradually prepares for sunrise.

It is also surprisingly cost-efficient. Dexia Tower's website claims that it uses about 1/3 less energy than the Eiffel Tower and 1/7 the energy used to light a football stadium.