WHEN A GROUP OF Spanish investors paid top dollar for land at Second and Congressional in Austin, they had big dreams. It was their first project in the United States, and they wanted to make a splash.

“The client’s vision was so strong that everyone on the team elevated their performance to an unparalleled level,” says R. Scott Ziegler, founding principal of Houston- based Ziegler Cooper Architects, which designed the project. “The client wanted the most sophisticated, elegant living possible in downtown Austin."

That’s what Ziegler Cooper accomplished with The Austonian, the tallest residential building in Austin. The 850,000-square-foot behemoth has an elliptical shape and floor-to-ceiling windows that reflect shimmering highlights throughout the day. The architect incorporated limestone and a neutral color, which is the predominant design scheme in Austin. The project, a 56-story tower topped by a green roof terrace, has first-floor retail and restaurants. The designers also embedded in the structure The Brown-Dumas Blacksmith Shop, which had existed at the property for a century.

Being in Austin, building green was a requirement. The designers achieved a four-star rating from Austin Energy Green Building, which is comparable to a U.S. Green Building Council LEED Gold rating, by investing in design, materials, and processes that support energy and water conservation.

Inside, the project team wanted a building that would draw Baby Boomers out of their suburban homes. So The Austonian features a 6,000-square-foot party space, a billiard and game room, wine vault, theater screening room, fitness center, outdoor swimming pool, and dog park.