Cities are dense with impermeable sidewalks and streets, so the concrete jungle doesn’t exactly drink up excess water during storms. The result: destructive flash floods. To help, Danish architecture firm Tredje Natur developed Climate Tiles, a modular paving system that collects and distributes rainwater. The slabs resemble a normal paved surface but sport small perforations that funnel storm runoff into horizontally connected channels. The system captures water from roofs, streets, and parking lots, and delivers it to nearby permeable landscapes—such as garden boxes or park spaces—where it can be absorbed. Tredje Natur already gave a few Copenhagen sidewalks a face-lift this year to test out the tiles. But even before that experiment is finished, Toronto and several other cities have put in requests for the rain-draining material.