When Marco Polo traveled overland from China to Europe he passed through what are now known as the Central Asian nations of Turkmenistan and Uzbekistan. It is a region with dozens of ethnic groups and languages, unspoiled countryside, brittle deserts and colorful ancient cities with names like Sammarkand, Bukhara, Khiva and Merv. From Krasnovodsk in Turkmenistan on the Caspian Sea to Kokand, Uzbekistan it is a little more than 1,000 miles and it can be traveled by train on the Trans-Caspian Railroad, built by the czar's military in the 1880's to expedite the capture of the ancient territories. It has been only since the breakup of the Soviet Union that the region has been open to westerners.