The One, Los Angeles

The One in Bel Air, Los Angeles — a 105,000 square foot mega-mansion completed in 2022 by developer Nile Niami after 10 years of construction — is the largest private home ever built in America. Containing 21 bedrooms, 42 bathrooms, a 30-car garage, a 400-foot outdoor running track, a nightclub, a 4D cinema, five pools, a beauty salon, and a helicopter pad, it sold in 2023 for $126 million.