Fifty feet below (0) DOWNTOWN (TOWN) Seattle, the world's largest tunnel-boring machine, nicknamed Bertha after the city's 1PROGRESS mayor, lies still. This 2REMARK vehicle weighs 7,000 tons, stretches nearly 330 feet long, and has a 60-foot diameter. When fully 3OPERATE, Bertha has an intrepid crew of 25. In early August, Bertha began carving out a two-mile road tunnel to replace the Alaskan Way viaduct, an ugly double-decker motorway that has been 4FIGURE Seattle's waterfront since the 1950s. Dozens of 5ALTER were considered, including twin tunnels, another elevated roadway, and even scrapping the highway in favor of improved surface roads and better public transport. As it happens, politicians dithered long enough for tunneling technology to develop 6SUFFICIENT facilitating another option: a single tunnel large enough to accommodate two levels of multi-lane traffic. Many local 7PRESENT are against Bertha, but she has already chewed up and spit out one politician. As the new mayor settles in to his new role, he will surely be hoping that Bertha 8SPEED finds her appetite for muck, not mayors.