One Last Thing: The Head of the Charles's Floating Traffic Cops

Even as the crush of its 300,000 cheering spectators ties up traffic on nearby roadways, the world-renowned Head of the Charles Regatta (10/18–10/19) transforms Boston’s normally serene river into something of an aquatic autobahn.

Helping keep its 7,500 rowers in line is a series of handmade buoys invented by course architect Sherry Proctor; without them, the twisting 3-mile path to victory “would be really tough to navigate,” course committee cochair Chris Richards says, with understatement. Constructed entirely by race volunteers, the 4-inch-high Styrofoam markers are cut to size with a bandsaw and spray-painted an eye-grabbing neon orange (for those on the port side) or green (starboard), then connected with elastic tethers to anchors made of concrete-filled PVC pipe.

High-tech they aren’t, but they’re practically cutting-edge compared with the plastic bleach bottles, painstakingly anchored with bricks, that race organizers used to rely on.