No one seems to gripe much anymore about how, in a globalized context, the very idea of national pavilions at an international exposition might seem anachronistic. Perhaps that’s because, for the time being at least, we’ve decided they’re not. Identity is a powerful thing, and the more than 50 national pavilions at this year’s Biennale—concentrated mostly in the Giardini, but also at the Arsenale and sites throughout town—remind us not only of our “Common Ground,” the Biennale’s theme, but also our differences.

The famously and perennially under-funded United States pavilion makes a strong showing this year with Spontaneous Interventions: Design Actions for the Common Good, under commissioner Cathy Lang Ho. The exhibition was organized by the Institute for Urban Design with curatorial assistance by Ned Cramer and David van der Leer. Scores of grassroots initiatives ranging from “guerilla bike lanes” to “urban repair squads” paint an optimistic picture of American civic engagement within a clever, interactive installation of banners, pulleys, and counterweights by Brooklyn design firm Freecell.