A gracious Riverside Drive mansion is back on the market for $25 million.

The landmarked Upper West Side property, located at 3 Riverside Drive and known as the Kleeberg Residence, was bought at auction for $15.8 million in 2017 — a stunning drop from its 2012 asking price of $40 million.

It stands 37 feet wide, and was built in the late 1800s in the French Renaissance Revival style, with gargoyles and cherubs carved into its facade.

Inside, the home is mid-renovation — the new owner will have to complete the work — and there are “approved” plans for, among other things, a “half Olympic-sized” marble lap pool and an onyx-walled hot tub.

The plans are by superyacht architect Achille Salvagni.

The previous owners were Regina Kislin — a broker/developer and daughter of metals trader Sam Kislin, a Soviet-era emigre who got his start with the late billionaire Soviet-born developer Tamir Sapir — and her husband, Anatoly Siyagine.

Kislin bought the residence, between West 72nd and West 73rd streets, for less than $10 million in 1995.

The current co-brokers are Ian Slater, of Compass, and Andrew Azoulay and Natalie Geiger, of Douglas Elliman.