Business owners, and land speculators such as Gurdon Saltonstall Hubbard, quickly set about rebuilding the city. The first load of lumber for rebuilding was delivered the day the last burning building was extinguished. By the World's Columbian Exposition 22 years later, Chicago hosted more than 21 million visitors. The Palmer House hotel burned to the ground in the fire 13 days after its grand opening. Its developer, Potter Palmer, secured a loan and rebuilt the hotel to higher standards across the street from the original, proclaiming it to be "The World's First Fireproof Building".