The very notion is deliciously ghoulish: What happens to earth if--or when--people suddenly vanished? The History Channel presents a dramatic, fascinating what-if scenario, part science fiction and part true natural science. "Welcome to Earth, Population: 0" is the catchy tagline, Life After People's 94 minutes are so gripping you nearly forget while you watch that you, yourself, will be gone too. It turns out that earth can go along very nicely without us. The hardest part of the special is probably in the first 15 minutes, when pet owners confront what likely will happen to their dogs (thankfully, the show follows those dogs who break out of their houses, and the prognosis for them to survive as scavengers is good). As the fictional days and weeks tick by, the process of nature's reclaiming the planet becomes less grim and more fascinating. The impact of the lack of people will be noticed right away, as most power grids shut down around the planet. The one holdout: Hoover Dam, whose hydro power lights up the American Southwest. Scientists say the dam can continue to operate on its own for months, maybe years, keeping the Vegas Strip alight. Only the eventual accumulation of quagga mussels, an invasive species, in the cooling pipes of the power plant--currently being cleaned by humans--will shut down the dam. Elsewhere, critters and plants will have their run of Manhattan and every other previously "civilized" spot. Inventive photography shows bears clambering out of subway stations, and vines pulling down brownstones, then skyscrapers. It may not be a surprise when the Eiffel Tower and Space Needle meet their eventual fates, but the scenes nonetheless provide a pleasant sting of shock. Life After People is humbling, yet exhilarating. -- A.T. Hurley