Before they developed an effective central government, it seemed that anywhere you turned in Scotland, there was a castle.

At one point, there was up to 3,000, which is about one for every hundred square miles in Scotland.

In just a minute, Scottish tour guides introduce us to their favourite castles to visit.

Some are ancestral homes for famous Scottish families, while others were important garrisons

against invaders. One of the grandest is Sterling Castle. It's not a clan castle, it's a

defensive castle, one of the oldest castles in Scotland. Head for the high out-acama desert

in northern Chile, and instead of castles, you'll find giant telescopes scattered about the desert.

Rubbed shoulders with the scientists during the day

and see what they're doing,

and then come back at night to look through telescopes

at some of the clearest skies you'll find anywhere on Earth.

Mark Johansen takes us to the driest place on Earth,

and listeners update us on their memorable adventures.

It's in the hour ahead on Travel with Rick Steves. Flocks of flamingos at 15,000 feet might make you feel like a bit of

an alien visitor when you climb to the high deserts of northern Chile. Coming up, journalist Mark

Johansson

takes us wandering in the Atacama

for breathtaking adventures

under the clearest skies on earth.

And we're overdue for a check-in with our listeners,

so we'll hear about your travel adventures

and help you plan for more.

...