The principal towns on the Danube are Ratisbon, Vienna, Pressburg,
Budapest, Belgrade, and Galatz. The width of the river varies
considerably, and at some points the opposite shore is hardly
discernible. It is first navigable at Ulm, and, thanks to various
improvements, is now navigable continuously from that point to its
mouth. Engineering work to this end, undertaken at Vienna, Budapest, and
the Iron Gates has already been referred to. The International Danube
Navigation Commission, appointed in 1856, controls the lower portion of
the river, and has done much to improve navigation at the delta.
Sea-going vessels of six hundred tons can now go nearly as far as the
Iron Gates, while vessels of twenty-five hundred tons can go above
Galatz. By means of canals the Danube is connected with the Rhine and
the Elbe.