Beginning in 1910, inventor and industrialist Chester Thordarson acquired most of Rock Island except the lighthouse area and developed it as a private retreat. He first renovated a nineteenth-century log house from the fishing village near the southeast shore for his residence, then in 1924 hired a crew to clear thirty acres on the west side of the island. A log lodge for his many guests was among the first buildings erected, and more structures followed in the 1920s, including a one-and-a-half-story chalet built in 1925 for entertaining his Chicago employees and friends. Deeply interested in nature, Thordarson created themed landscapes, built a distinctive greenhouse with a fieldstone foundation, cornerstone pillars, and an attached cobblestone cottage with a green Spanish tile roof, and used the greenhouse for botanical experiments and for growing fragile species he wanted to protect. Known for preserving the natural landscape, native animals, and wildflowers, he limited development on the island. After the attack on Pearl Harbor, he ordered the Japanese garden destroyed as a display of patriotism. The island's buildings and grounds reflected his romantic vision of a replica of his native Iceland, using local wood and stone and providing everything needed to entertain guests, who boated, fished, and hiked there; he even built a cottage for Chicago mayor "Big Jim" Thompson.