BIG's concept includes a lawn between the Smithsonian’s historic Castle and Independence Avenue that curls upward at its corners.

To interest donors in a plan that includes HVAC upgrades and the repositioning of loading docks, it helps to throw in a few dramatic flourishes. That’s the lesson of the Smithsonian Institution’s new master plan, made public today in Washington, D.C., by the Institution’s secretary, Wayne Clough, and his architect of choice, Bjarke Ingels, of the Copenhagen- and New York-based Bjarke Ingels Group.

Much of the plan, which will take decades and at least $2 billion to implement (and is dependent on a mix of public and private funds), involves invisible infrastructure improvements, which, Clough said, are “hard to get people to write checks for. You have to show them the big concept.” That big, or BIG, concept includes a lawn between the Smithsonian’s historic Castle and Independence Avenue that curls upward at its corners.

The canted lawn is certainly photogenic—it resembles a lawn proposed by Ingels for Brooklyn Bridge Park, as well as the lawn at Lincoln Center created by Diller Scofidio + Renfro as part of a $1 billion renovation of that complex (a close analogue to the Smithsonian project, involving improvement to the “visitor experience” and replacement of aging mechanicals).

Luckily, the peeled-up lawn is more than a gimmick. Two of the Smithsonian’s units—the Arthur M. Sackler Gallery (devoted to Asian Art) and the National Museum of African Art—are nearly invisible, parts of a vast subterranean complex that are now entered through what appear to be gazebos. The new lawn, with its corner entry pavilions and strip of windows linking them, will make the two museums easier to see and enter.

The Smithsonian already has an overall master plan, but it believed its South Mall campus, along Independence Ave. SW, from 7th to 12th Street—that is, from the Freer Gallery of Art to the Hirshhorn Museum—needed special attention. In 2013 it announced it had settled on BIG, which is working with the San Francisco-based landscape architecture firm Surfacedesign Inc. The process, guided by Clough, took on new urgency in 2011, when an earthquake rocked Washington. Clough, a civil engineer, was in his office in the Castle at the time. As seismic forces ground up century-old mortar, his office, he remembers, filled with dust. One expensive component of the master plan is a seismic upgrade, which will consist of “base isolation”—essentially putting the Castle on a tray, so if another earthquake hits, “the building won’t even know it’s happening,” Clough said. Digging for the tray will permit the creation of new underground facilities, including an auditorium, education spaces, and cafeteria. Above ground, flanking the canted lawn, Ingels promised both “restoration of the romantic, meandering paths” and more intuitive links between the buildings.

At the Hirshhorn, a plan by Diller Scofidio + Renfro for a balloon-like conference space inside the donut was shelved last year, and Ingels’ proposal for that building, designed by Gordon Bunshaft, is modest: It calls for taking down the wall that separates the building from the Mall, and tweaking the courtyard with a new fountain and ramp. It also calls for the creation of underground spaces for contemporary sculptures too big for the existing galleries. But, oddly, the plan largely sidesteps the Smithsonian’s Arts and Industries building, a handsome masonry structure adjacent to the Castle. That building was recently renovated, but is unoccupied; Clough said Congress will have to decide what to do with it. But critics of government waste are likely to wonder: why build new facilities when a prominent building sits empty?