HOUSTON – The Downtown Aquarium is planning a massive renovation for one of its most popular exhibits.

The tiger habitat underwent a $4 million makeover to add a new outdoor space. This move has been many years in the making and is a part of the aquarium’s mission to provide the best quality of care and welfare of its animals. The 35,000 square foot expansion houses four tigers.

Before the upgrades, the tiger habitat was the center of some controversy.

The Animal Legal Defense Fund filed a federal lawsuit under the Endangered Species Act, claiming the four tigers who have been at the aquarium since 2004 had not been outside for more than 13 years. The group put the lawsuit on hold when the aquarium began planning for the outdoor space.

The new exhibit opens to the public Friday at 10 a.m.