Designs for the last piece of the national mall have been unveiled and include designs from 6 of the most recognized names in architecture. The entries include submissions from Devrouax +Purnell Architects & Pei Cobb Freed & Partners, Diller Scofidio + Renfro in Association with Kling Stubbins, Foster + Partners / URS Group, Inc., Freelon Adjaye Bond / Smith Group, Moody Nolan Inc. / Antoine Predock Architecture PC, & Moshe Safdie and Associates Inc. The site for this new half a billion dollar LEED certified building will be on the corner of 14th street and Constitution Ave, directly opposite the American History Museum. According to The Washington Post Models of these submissions are on display to the public at the Castle Building until April 6th, and if these models are anything like the renderings then you should probably take a few hours out of your day to check it out! The Castle building is located opposite the Natural History Museum on The Mall.