Great is the art of beginning, but greater the art is of ending.
—Henry Wadsworth Longfellow
You've grabbed attention in the opening, sustained it through the transitions, and now all you have to do is close. It may seem like a time to wind down, to simply sum up and breathe a sigh of relief. And, of course, it's not. For no matter how vivid the words that came before, your conclusion is your prime time; it's what your whole speech should build toward. Don't throw it away. Instead, build up to it, and make sure it is stimulating and memorable.
What do people remember most? What they hear last. Yet so few speakers devote any thought or preparation to their ending. They just fade away and they and their messages are soon forgotten. To be truly memorable you must end as strongly as you began.
I've seen people so relieved their stint on the podium is over that they start to pack up before they finish speaking. Powerful speakers save a lot of energy and concern for the audience until the end, and make the conclusion their dessert: something delicious, with a memorable aftertaste.