Attempts to form permanent settlement colonies west of the Great Lakes were beset by difficulty and isolation until the building of the Canadian Pacific Railway and the second of the two Riel Rebellions. Despite the railway making the region more accessible, there were fear that a tide of settlers from the United States might overrun British territory. In 1896, Minister of the Interior Clifford Sifton launched a program of settlement with offices and advertising in the United Kingdom and continental Europe. This began a major wave of railway-based immigration which created the farms, towns and cities of the Prairie provinces.