The culmination is the end point or final stage of something you've been working toward or something that's been building up. The culmination of your high school career, for example, should be graduation day — and probably not prom night.
A culmination isn't just the conclusion. It's the climax of the story, the final crowning achievement, the end result of years of research. “Life is a culmination of the past, an awareness of the present, an indication of a future beyond knowledge, the quality that gives a touch of divinity to matter,” said Charles Lindbergh, the first solo pilot to fly nonstop across the Atlantic — a feat that was surely the culmination of his aviation career.