Going as far into the sky as you can go on foot, you'll reach the highest point, or pinnacle, of the Himalayas. A successful climb like that might also become the pinnacle, or peak, of your success.
Two synonyms for pinnacle also start with the letter "p," "peak" and "point." A pinnacle can be a physical thing, like the top of a high mountain or the antenna on the very top of a building, or it can be a high point that can’t be measured with a ruler, like an achievement or a goal. Whatever the pinnacle is, reaching it is almost always a completion of something where you have gone the highest you can go. "Acme" is a great synonym for pinnacle.