Something that is the highest or most exciting point is climactic. This adjective is used to describe a scene, event, or action. If you enjoy a good mystery, you probably love the climactic ending, when you find out whodunnit.
Climactic describes the grand finale or the top point of a series of events, and it comes from the word climax. The climactic scene in The Wizard of Oz is when Dorothy and friends face the Wicked Witch of the West, for example. When you finally reach the top of a mountain, you’re at the climactic point! Realizing that mountain’s just a landfill, well, that’s anticlimactic.