Famed blue domes on white buildings. There are thousands of Greek islands and hundreds of them are inhabited. Santorini is one of the most popular. I just went for a day trip from Athens so it was a whirlwind (sorry, no nosh and no nip). The island is basically three main parts...Fira (in the center, where the airport is), Oia (north, where the blue dome buildings are), and Akrotiri (the south, where the ruins of an ancient city are being excavated). If I could do it over, I would stay at least one or two nights on the island.

Nav:

Oia: Pronounced 'E-ah'. There weren't as many blue domed buildings as I thought. Apparently these are iconic roofs of churches, not homes. The streets of the town are walkable, but can be steep in places. There are a lot of little shops, restaurants, and places to stop off for a glass of wine.
Pro Tip: Cruise ships pull into the area and shuttle passengers to the base, where they can pick up a donkey ride to the top. Be prepared for crowds at peak season. Also, the vantage points for seeing the blue domes are limited.

Akrotiri Archaeological Site: The site dates from about 3,000 BC. The city was buried in volcanic ash. From the excavation, it appears citizens left town...unlike the people of Pompeii. The nearby Red Beach is named for the color of the cliffside. The black sand on the beach is the result of volcanic material mixed in the sand. You can swim, snorkel, and sunbathe here...but I was on a day-trip so I didn't bring a swimsuit.