Ostrovsky Park is the main attraction of Korosten. Every year in September, the festival of deruny (hash browns) is held in the park. Besides it, you can visit the locomotive depot museum (for those who are interested) and walk along the central Hrushevsky Street.
The park is located in the downtown, on the granite banks of the Uzh river. The main improvement has occurred in recent years. A bridge across the river, a huge statue of Prince Mal and other sculptures as well as many walking paths were built. Many citizens donated money for restoration of the park.
In general, the park is very convenient to come here from Kyiv. 1.5 hours were enough for us to walk around, the park is not large. There are no photos of the fountains, since we were there in November, and they no longer worked.

Monument to the future Prince Vladimir and his mother Malusha in the Ostrovsky Park in Korosten ©Yuriy Buriak
At the top of the hill stands a monument to Prince Mal, who ruled in the X century. It was established in honor of the 1,300th anniversary of Korosten.
Also wooden fortifications of the ancient city of Iskorosten were built here.
Under the hill with the statue is the Skelya (Rock) object. It is a military museum of the former secret command center, which was built in 1935-37. There's about 30 rooms inside the rock.
Getting there: Korosten has a good location on the Warsaw highway. Minibuses from Kyiv go from the Sviatoshyn metro station (from here). 2 hours to go, ticket price is $6. You can ask for a stop near the Ostrovsky Park. The minibuses go back to Kyiv from the train station, platform #10. Korosten is a major railway junction, however, better use a bus, as the Warsaw highway is in good condition.