Anticipated, delayed, and debated, The Broad opens its doors to the public on September 20. Plans for Diller Scofidio + Renfro’s contemporary art museum for the collectors and philanthropists Eli and Edythe Broad were first unveiled in early 2011. Four years later, deep into the Instagram age, the photogenic $140 million building wove itself into Los Angeles’s digital and cultural fabric long before the ground floor shed was removed.

Taking up real estate on Grand Avenue, the 120,000-square-foot museum isn’t an icon of the likes of neighbor Gehry’s Disney Hall or nearby High School #9 by Coop Himmelb(l)au—both projects supported in myriad ways by Eli Broad. It’s a box with a fancy skin, not an exuberant gesture.

For a long time, Broad has maneuvered to position Grand Avenue to be Los Angeles’s prime cultural destination, with mixed results. The new museum opens with a 24,000-square-foot public plaza designed by DS+R and landscape architect Walter Hood. Planted with 100-year-old Barouni olive trees, and a hip restaurant soon to open, the outdoor space is a small buffer against the surrounding hardscape. Little attention has been given to Hope Street, and 2nd Street greets visitors with an undistinguished parking lot entrance.

The DS+R design is in service of two things in and above its form: a personal art collection of 2,000 artworks and Grand Avenue itself. In short, the architecture is in tension between private and public responsibilities.

DS+R, who partnered with executive architects Gensler, describes the museum’s two big architectural moves as “the veil” and “the vault.” Wrapping most of the building, the veil is both facade and roof. The assembly of 2,500 fiberglass reinforced concrete (GFRC) panels (supported by 650 tons of steel) lifts at the corners to reveal glass entry doors and sucks in along Grand Avenue to form a belly button-like oculus.

The veil has also been the source of dispute. First, critique was leveled at the project when it was revealed that the concrete latticework was no longer wholly structural, as the original proposal in the vein of the L.A.’s American Cement Building, suggested. Then Broad and Matt Construction sued Seele Inc., a Germany-based engineering company fabricating the honeycomb facade, claiming delays and unsuitable mock-ups.

But for all the controversy, the facade is a study in low relief and slight variation. In truth, the veil is not in service of the public nor the Grand Avenue urban corridor, but rather ministers to the needs of the interior: 318 meticulously shaped skylights filter northern light into the third floor gallery. The 35,000-square-foot, column-free space is vast, luminous, and during the current exhibition is filled with partition walls hung with late 20th-century masterpieces, a necessary division for a flexible museum, but one that nonetheless lessens the overall impact.

The vault is just that—21,000 square feet of collection storage (as well as Broad Foundation offices) located in the center of the structure. Sandwiched by ground floor exhibition spaces below and the main gallery above, the vault is home to row after row of storage racks for paintings and photographs and cold storage for media art. According to archive staff, the museum was designed for 15 to 20 percent collection growth. However, The Broad’s voracious collecting has shrunk that extra capacity down to 8 to 10 percent.

The visitor experience knits together the public and the private, the veil and the vault. The Broad’s three circulation routes prove the most successful architectural experiences: a 105-foot escalator cuts through the lobby’s gray, hand-trowelled plaster walls and deposits visitors in the third floor gallery; a cylindrical glass elevator lifts dramatically through the building’s layers; and a central stairwell winds back down from the gallery to the lobby. Windows offer tantalizing glimpses into the art storage vaults. While the museum has a robust collection of art world pleasers and DS+R’s scheme offers some much-needed amenities along Grand Avenue, it is the small frisson of seeing something generally hidden from public view that offers the most private of pleasures.