culmination — Something, especially something important, that is the culmination of an activity, process, or series of events happens at the end of it.
capstone — one of a set of slabs on the top of a wall, building, etc
turning point — a point at which a decisive change takes place; critical point; crisis.
acme — The acme of something is its highest point of achievement or excellence.
apex — An Apex or an Apex ticket is a ticket for a journey by air or rail which costs less than the standard ticket, but which you have to book a specified period in advance.
apogee — The apogee of something such as a culture or a business is its highest or its greatest point.
ascendancy — If one group has ascendancy over another group, it has more power or influence than the other group.
limit — the final, utmost, or furthest boundary or point as to extent, amount, continuance, procedure, etc.: the limit of his experience; the limit of vision.
maximum — the greatest quantity or amount possible, assignable, allowable, etc.
orgasm — the physical and emotional sensation experienced at the peak of sexual excitation, usually resulting from stimulation of the sexual organ and usually accompanied in the male by ejaculation.
payoff — the payment of a salary, debt, wager, etc.
