qnli question: The previous record beaten by Park Avenue was for what real estate? sentence: 450 Park Avenue was sold on July 2, 2007 for US$510 million, about $1,589 per square foot ($17,104/m²), breaking the barely month-old record for an American office building of $1,476 per square foot ($15,887/m²) set in the June 2007 sale of 660 Madison Avenue.