National Gallery of Art two months after excavation had begun. At the time of its inception it was the largest marble structure in the world. The museum stands on the former site of the Baltimore and Potomac Railroad station, where in 1881 a disgruntled office seeker, Charles Guiteau, shot President James Garfield (see James A. Garfield assassination). As anticipated by Mellon, the creation of the National Gallery encouraged the donation of other substantial art collections by a number of private donors. Founding benefactors included such individuals as Paul Mellon, Samuel H. Kress, Rush H. Kress, Ailsa Mellon Bruce, Chester Dale, Joseph Widener, Lessing J.
Charles R. Skinner in Washington D.C. in 1882, and had been asked to attend the execution of Garfield's assassin, Charles Guiteau, but was unable to attend due to the illness of his daughter. He was invited to Czolgosz's execution by the warden of Auburn Prison, and attended as one of only twelve "official" witnesses to the execution as required by New York law. Less than two months after shooting McKinley, Czolgosz was executed on October 29, 1901 in Auburn Prison. Czolgosz was executed in the electric chair, an early usage of this new form of execution. Thomas Edison later re-enacted the execution in