This is the United States Institute of Peace. It is located at 2301 Constitution Avenue NW in Washington, D.C. 20037. It was built in 1984 on the last peace of land available on the mall. It is a federal project, created by our government. So it is ours.
Their website (https://www.usip.org/) says, "USIP is America’s nonpartisan institute to promote national security and global stability by reducing violent conflicts abroad. Our staff guide peace talks and advise governments; train police and religious leaders; and support community groups opposing extremism—all to help troubled countries solve their own conflicts peacefully."