14
The first thing a visitor to Earth discovered was that Earth didn't have just one Skyhook, like Mars. Earth had three of them. The reason was that there was a lot more ground-to-space traffic for Earth than for any other planet, and all three of its Skyhooks were kept busy.
They all, of course, had to touch ground at Earth's equator, because it is only over the equator that a geostationary satellite can stay in position. The one in Ecuador was the busiest, although the mountains around Quito made transshipment a problem. The one at Pontianak was the newest, and maybe some day it would be the best because its location right on a coast made the transshipment of bulk goods very practicable—or at least it would do that whenever the Martians finally succeeded in growing enough produce to ship to Borneo to matter. Until then, Pontianak had so little traffic that it still used only a single cable. But the one in Kenya was in some ways the best, not least because it was handy to all the businesses and industries of that very big African city called Nairobi.
Nairobi was so big and busy that people forgot that it was only accidentally a city. It didn't have most of the things that cities grow up around. It had no river or port or anything else to distinguish it from all the highland plains that surrounded it. It existed simply because it happened to be a convenient place for the developers to put a station stop when, long ago, the first railroad was built from the heart of Africa to the coast. Now that same place was still a station stop—though of a markedly different kind—and it was prospering therefrom.