Denise Rich is a very successful songwriter, socialite, heiress, ex-wife of Swiss financier Marc Rich, and now owner of the most expensive co-op currently on the real estate market in NYC, according to Zillow.com. The Fifth Avenue triplex includes 20 rooms, with seven bedrooms, 11 bathrooms, three kitchens, gym, wrap-around terraces, full roof terrace, and amazing views of the Manhattan skyline and Central Park. Now that Rich's two daughters have left the nest, she is finally ready to downsize. Last year the most expensive cooperative in New York City was the $88 million apartment on Central Park West formerly owned by Chase founder Sandy Weill.

Go to Zillow.com to learn more.