972 Fifth Avenue houses the cultural services of the French Embassy in the U.S., but when it was first built in the early 1900s it was home to one of the city's wealthier families of the Gilded Age. 

"It was a Whitney family mansion. This house is really a love story. It was given as a wedding gift. Not a bad wedding gift," said Benedict de Montlaur, Cultural Counselor of the French Embassy.

The Payne Whitney Mansion is one of the places opening to the public for this year's Open House New York weekend, this Saturday and Sunday. It's the fifteenth year for this annual celebration of architecture and urban design. 

"250 buildings and sites all across all five boroughs over the weekend. More than half of them will be open free of charge. You just show up during the days and hours listed - and have a great time," Gregory Wessner, Executive Director of Open House New York.

The Mansion will open Saturday afternoon.

Cultural Counselor for the French Embassy Benedict de Montlaur gave NY1 a tour around the beautiful home of Payne Whitney and Helen Hay, from prominent New York families so no expense was spared by famous architect Stanford White.

It's open to the public daily, but there will be more access than usual on Saturday. 

"What we are doing special for Open House New York is that we are opening some upper floors that are usually closed to the public. So we are showing some of our best kept secrets," said Benedict de Montlaur, Cultural Counselor of the French Embassy.

A statue replica of a Michelangelo which sat in the place practically unnoticed for years the real one is across the street at The Met. And a dress belonged to Marilyn Monroe. But the de Montlaur says they are not sure how it got here. 

"We are pretty sure that it belonged to her but the mystery remains, we don't know why it is here, because to our knowledge, she never came to the French Embassy," said Benedict de Montlaur, Cultural Counselor of the French Embassy.

Many of the places available for visitors for Open House New York Weekend are older, like this place. But there's also newer destinations too that are part of the tours.

"It's not just about historic preservation, it's really about looking at the city in its totality,"said Gregory Wessner, Executive Director of Open House New York.

To find out more about what's out there this year, head to OHNY.org.