Overview
Huacachina, the place that made me say "so real oases actually exist." Peru is such a fantastical country that during the 4-hour Lima-Ica drive, the landscape shifts from arid to tropical and then turns into complete desert, with an oasis right in the middle of it.
What to See
The views inside the oasis are gorgeous, set aside plenty of time for photos. Afterward, for about 15 dollars (you can find cheaper), take a desert safari with loads of sandboarding. The desert wasn't too hot when we visited, so we really enjoyed it. Sliding down the dunes is fun on its own, and racing down sand hills in big desert jeeps is a whole other level of excitement. The sunset scenery was absolutely breathtaking. The oasis looks fantastic at night too.
Tips & Advice
If you're visiting Lima independently, don't be lazy, definitely add this to your day-trip itinerary.
One more note: if you're heading into the desert in regular shoes, consider some kind of gaiter or cover to keep sand out. Otherwise, prepare to keep finding sand in your shoes for the rest of your trip.