The Croatian coast stretches for about 1,800 kilometres if you follow every bay, peninsula and inlet. That is roughly the distance from London to Rome! The water is clear enough in many places that you can see the rocky bottom several metres down, and small silvery fish dart around your feet.
Most of the islands were formed thousands of years ago when the sea rose and flooded the tops of ancient mountain ridges, leaving only the peaks above water. That is why so many Croatian islands are long and narrow, running from north to south in neat rows, like mountains lying on their sides.
The islands have different personalities. Korčula has a medieval old town crammed with narrow stone streets. Vis is famous for its bright blue sea caves. Mljet has a saltwater lake right in the middle of the island where you can swim. And Brač has a beach called Zlatni Rat where the sand actually changes shape depending on the direction of the wind and waves.
In summer, dolphins are often spotted leaping alongside ferries in the open sea between the islands. Locals call the Adriatic 'the sea you can drink' - not because you actually drink it, but because it is so clear, clean and calm compared with the open Atlantic.