A posh Park Avenue pad is about to hit the market for $14.99 million, from the estate of the late Anna-Maria and Stephen Kellen.

The philanthropic couple most famously established the American Academy in Berlin, Stephen’s birthplace, to fund and maintain cultural ties between the US and Germany.

Stephen, who was married to his wife for 64 years at the time of his death (at age 89 in 2004), was also a member of the Council on Foreign Relations.

Anna-Maria, who was also born in Berlin, died this past April at age 98. Their co-op is a 14-room duplex on the 16th and 17th floors of 784 Park Ave., with views stretching across Central Park.

The five-bedroom unit features its own elevator landing on both floors, a glass conservatory and a grand salon with a woodburning fireplace.

It also has a terrace, a formal dining room, an eat-in chef’s kitchen and lots of storage.

Neighbors in the building include Robert Hormats, vice chairman of Kissinger Associates and a former Under Secretary of State for Economic, Business and Agricultural Affairs from 2009 to 2013, and his wife Catherine, and the art dealer Irving Blum.

The listing agents are Barbara Evans-Butler and William Vitiello of Stribling & Associates, and Claire Groom of Warburg.