On the way south, the English discovered the mountains of central Switzerland. Several spa and bathing resorts such as Weggis or Gersau were created. In 1871, the very first rack railway in Europe, the Vitznau-Rigi Railway, was opened. In 1889 the steepest cog railway in the world was built from Alpnachstad to Mount Pilatus. Mark Twain described an ascent to the Rigi, which led to the blossoming of Swiss tourism in the United States in the 19th century. One of the largest steamship fleets in Europe operates with five steamships on Lake Lucerne.