Dear Mabel,

Well, here we are, as promised. They've given us a permit to live in the Valles Marineris, and don't think we haven't been waiting for a year and a half because we have. They're so slow and they keep talking about the capital investment required to make the place livable.

Valles Marineris sounds good as an address, but we just call it the Canyon, and I don't know why they're so worried about its being livable. It's the Martian Riviera, if you ask me.

In the first place, it's warmer down here than it is in the rest of Mars, a good ten degrees (Celsius) warmer. The air is thicker-thin enough, heaven knows-but thicker and a better protection against ultraviolet.

Of course, the main difficulty is getting in and out of the Canyon. It's four miles deep in places and they've built roads here and there so that you can get down in special mobiles. Getting up and out is more difficult, but with gravity only two-fifths what it is on Earth, it isn't as bad as it sounds, and they do say they're going to build elevators that will take us at least partway up and down.

Another problem is, of course, that dust storms do tend to accumulate in the Canyon more than on the ordinary surface, and there are landslides now and then, but heavens, we don't worry about that. We know where the faults are and where the landslides are likely to occur and no one digs in there.

That's the thing, Mabel. After all, everyone on Mars lives under a dome or underground, but here in the Canyon, we can dig in sideways, which I understand is much preferable from an engineering standpoint, though I've asked Bill not to try to explain it to me.

For one thing, we can heat out some of the ice crystals, so that we don't have to depend on the government for all the water we need. There is more ice down in the Canyon than elsewhere and, for another, it's easier to manufacture the air, keep it inside the diggings, and circulate it when you're in horizontally instead of down vertically. That's what Bill says.

And I've been thinking about it, Mabel. Where's the need to leave the Canyon, anyway? It's over three thousand miles long and in the end there are going to be diggings all along it. It's going to be a huge city, and I'll bet you most of the population of Mars will end up here. Can't you see it? There's to be some kind of maglev rail running the length of the Canyon and communication will be easy. The government ought to put every bit of money it can into developing it. It will make Mars a great world.

Bill says (you know what he's like-all enthusiasm) that the time will come when they will roof in the whole Canyon. Instead of having air just in separate diggings, and having to put on a spacesuit when you want to travel about, we will have a huge world of normal air and low gravity.

I said to him that the landslides might break the dome and we would lose all the air. He said that the dome could be built in separate sections and that any break would automatically shut off the affected areas. I asked him how much all that would cost. He said, "What's the difference? It will be done little by little, over the centuries."

Anyway, that's his job here, now. He's got his master's license as an Areo-engineer, and he's got to work out new ways to make the Canyon diggings even better. That's why we got our new place here and it looks as though Mars is going to be our oyster.

We may not live to see it ourselves, but if our great-grandchildren make it to 2140, a century from now, we'll have a world that may well overshadow Earth itself.

It would be wonderful. We're very excited, Mabel.

Yours, Gladys.