Oia (pronounced ee`yah) is the northern town on the island and is world famous for its spectacular sunsets!
Since public transit is limited and buses don’t run everywhere, you may want to rent a quad in Santorini to get around the island. As Santorini is only 30 square miles, you can reach any part of the island by quad or ATV. I recommend starting at one end of the island and heading to the other one.