From the Arabian Peninsula, we look at an ancient caravan route through the desert to Syria. ; Along the way, several lush oases in the otherwise barren Syrian desert come to our rescue in the form of Marib and Petra, cite of the great tomb of Aaron that is carved out of a rock face, along with the beautiful city of Palmyra in Syria. Early development The period from the middle of the 2nd millennium BCE to the beginning of the Common Era saw societies in Western Asia, the Mediterranean, China and the Indian subcontinent develop major transportation networks for trade. One of the vital instruments which facilitated long distance trade was portage and the domestication of beasts of burden. Organized caravans, visible by the 2nd millennium BCE, could carry goods across a large distance as fodder was mostly available along the way. The domestication of camels allowed Arabian nomads to control the long distance trade in spices and silk from the Far East to the Arabian Peninsula. Caravans were useful in long-distance trade largely for carrying luxury goods, the transportation of cheaper goods across large distances was not profitable for caravan operators. With productive developments in iron and bronze technologies, newer trade routes—dispensing innovations of civilizations—began to rise. Maritime trade Evidence of maritime trade between civilizations dates back at least two millennia. Navigation was known in Sumer between the 4th and the 3rd millennium BCE, and was probably known by the Indians and the Chinese people before the Sumerians. The Egyptians had trade routes through the Red Sea, importing spices from the "Land of Punt" (East Africa) and from Arabia. Evolution of Indian trade networks. The main map shows the routes since Mughal times, Inset A shows the major prehistorical cultural currents, B: pre-Mauryan routes, C: Mauryan routes, D: routes c. 1st century CE, and E: the "Z" shaped region of developed roads. Maritime trade began with safer coastal trade and evolved with the manipulation of the monsoon winds, soon resulting in trade crossing boundaries such as the Arabian Sea and the Bay of Bengal. South Asia had multiple maritime trade routes which connected it to Southeast Asia, thereby making the control of one route resulting in maritime monopoly difficult. Indian connections to various Southeast Asian states buffered it from blockages on other routes. By making use of the maritime trade routes, bulk commodity trade became possible for the Romans in the 2nd century BCE. A Roman trading vessel could span the Mediterranean in a month at one-sixtieth the cost of over-land routes. Visible trade routes The peninsula of Anatolia lay on the commercial land routes to Europe from Asia as well as the sea route from the Mediterranean to the Black Sea. Records from the 19th century BCE attest to the existence of an Assyrian merchant colony at Kanesh in Cappadocia (now in modern Turkey). Trading networks of the Old World included the Grand Trunk Road of India and the Incense Road of Arabia. A transportation network consisting of hard-surfaced highways, using concrete made from volcanic ash and lime, was built by the Romans as early as 312 BCE, during the times of the Censor Appius Claudius Caecus. Parts of the Mediterranean world, Roman Britain, Tigris-Euphrates river system and North Africa fell under the reach of this network at some point of their history.