Back here on Earth, there are also some sizable Engineering projects that are either under way, or planned:
- Back during the cold war, the United States looked into getting a Peace Dividend out of its nuclear weapons in terms of large-scale earth-moving capability. Codenamed Project Plowshare, the idea was to use nukes to carve out new harbors where none existed before. I seem to remember that the Soviets actually did use this method once, with spotty results.
- And speaking of nukes, the Chinese have looked into using them to blast a hole through the Himalayas in order to divert the output of a large river onto Chinese soil. As the river currently irrigates much of northern India, this has the Indians worried.
- And speaking of the Chinese, let's not forget the Great Wall of China, which was (and I think still is) the largest structure ever built by humans...and back in antiquity, too!
- Hong Kong's new airport might also deserve a mention here. Since there's not enough real estate on the island to handle the necessary air traffic, they're building the whole thing on a new man-made extension to the island.
Ok, now back to the sci-fi. In addition to the space elevator, Kim Stanley Robinson's Mars trilogy also makes use of a soletta to heat Mars to more terrestrial levels. This is basically a really really big array of orbiting mirrors, focused on a central reflector of about 1/2 degree diameter as seen from the surface. The result is an earthlike sun for a planet farther out in orbit.
Kind of a spoiler follows.....
Later in the series, the soletta is removed from martian orbit, and becomes an enormous parasol for Venus, as the first in the terraforming of that planet.