The city has long been a popular attraction for tourists. Between 1915 and 1930, Havana hosted more tourists than any other location in the Caribbean. The influx was due in large part to Cuba's proximity to the United States, where restrictive prohibition on alcohol and other pastimes stood in stark contrast to the island's traditionally relaxed attitude to leisure pursuits. A pamphlet published by E.C. Kropp Co., Milwaukee, WI, between 1921 and 1939 promoting tourism in Havana, Cuba, can be found in the University of Houston Digital Library, Havana, Cuba, The Summer Land of the World, Digital Collection.