The heart of Vienna lies within its famous Ringstrasse—a circular road completed nearly 150 years ago punctuated with Neo-Renaissance, Neo-Baroque, and Neo-Gothic monuments, and later, icons of Viennese Secession architecture. Like most modern capitals however, Vienna has expanded well beyond its historic center. In recent decades, the city has embraced a part of its geography it had long shied away from—the fabled Danube River.

Donau City, or Danube City, began to rise 20 years ago on the river’s northern banks with buildings by Pritzker Prize-winning local architect Hans Hollein, among others. Following an international competition in 2002, developer WED called on Paris-based Dominique Perrault to design the final section of the new district, overlooking the river. The French architect was in Vienna last week to officially open his DC Tower 1, which at 820 feet is now the tallest building in Austria.

The slim structure—it is 92 feet wide and 194 feet long—is the first of two towers Perrault has designed for the site. The second, expected to be completed within the next two years, will top off at only 551 feet. The design was conceived as two pieces of a giant monolith that split into unequal halves and open to create undulating, shimmering surfaces where the rupture occurred. While the façade of the completed building features a straightforward design on three sides, one of the larger faces is marked by folded glass planes that appear to weave in and out along the length of the tower. “The idea was to create a very specific urban space with a piazza between the two buildings,” explains Perrault. “While one face of the tower refers to the broken monolith, it is also meant to be a liquid façade evoking the surface of the river. With the second tower, they will act as waterfalls on two sides of the public space, and will be an amazing entrance gate for the district farther inland.”

The 60-story, mixed-use Tower 1 contains shops and a hotel on the lower levels, and offices and lofts above. It culminates in a restaurant and sky bar on the top floor. The stark interiors, designed with Gaëlle Lauriot-Prévost, Perrault’s artistic director and collaborator for more than 20 years, feature exposed concrete throughout, and stone and metal in lobbies and circulations areas. Metal umbrella-like structures are installed at the base of the tower to block wind.

With its exceptional height, Tower 1 has quickly become a Vienna landmark. But according to Perrault, it doesn’t neglect the city’s architectural past. “The example of Vienna is to develop a special skyline identity for the area around the historic center. This tower is part of that skyline, one that hopefully works like a new ring around the center.”