Explorers Of The United States

Exploration refers to the historical practice of discovering remote lands. It is studied by geographers and historians.

Two major eras of exploration occurred in human history: one of convergence, and one of divergence. The first, covering most of ''Homo sapiens'' history, saw humans moving out of Africa, settling in new lands, and developing distinct cultures in relative isolation. Early explorers settled in Europe and Asia; 14,000 years ago, some crossed the Ice Age land bridge from Siberia to Alaska, and moved southbound to settle in the Americas. For the most part, these cultures were ignorant of each other's existence. The second period of exploration, occurring over the last 10,000 years, saw increased cross-cultural exchange through trade and exploration, and marked a new era of cultural intermingling, and more recently, convergence.

Early writings about exploration date back to the 4th millennium B.C. in ancient Egypt. One of the earliest and most impactful thinkers of exploration was Ptolemy in 2nd century AD, Between the 5th century and 15th century AD, most exploration was done by Chinese and Arab explorers. This was followed by the European Age of Discovery after European scholars rediscovered the works of early Latin and Greek geographers. While the Age of Discovery was partly driven by European land routes becoming unsafe, and a desire for conquest, the 17th century saw exploration driven by nobler motives, including scientific discovery and the expansion of knowledge about the world. This broader knowledge of the world's geography meant that people were able to make world maps, depicting all land known. The first modern atlas was the ''Theatrum Orbis Terrarum'', published by Abraham Ortelius, which included a world map that depicted all of Earth's continents.

Concept

Notable historical periods of human exploration

Phoenician galley sailings

The Phoenicians (1550 BCE–300 BCE) traded throughout the Mediterranean Sea and Asia Minor though many of their routes are still unknown today. The presence of tin in some Phoenician artifacts suggests that they may have traveled to Britain. According to Virgil's Aeneid and other ancient sources, the legendary Queen Dido was a Phoenician from Tyre who sailed to North Africa and founded the city of Carthage.

Carthaginean exploration of Western Africa

Hanno the Navigator (500 BC), a Carthaginean navigator who explored the Western Coast of Africa.

Greek & Roman exploration of Northern Europe and Thule

* Pytheas (4th century BC), a Greek explorer from Massalia (Marseille), was the first to circumnavigate Great Britain, explore Germany, and reach ''Thule'' (most commonly thought to be the Shetland Islands or Iceland).
* Under Augustus, Romans reached and explored all the Baltic Sea.

Roman explorations

;Africa exploration
The Romans organized expeditions to cross the Sahara desert along five different routes:

* through the western Sahara, toward the Niger River and Timbuktu.
* through the Tibesti Mountains, toward Lake Chad and Nigeria.
* through the Nile river, toward Uganda.
* through the western coast of Africa, toward the Canary Islands and the Cape Verde islands.
* through the Red Sea, toward Somalia and perhaps Tanzania.

All these expeditions were supported by legionaries and had mainly a commercial purpose. Only the one done by emperor Nero seemed to be a preparative for the conquest of Ethiopia or Nubia: in 62 AD two legionaries explored the sources of the Nile.

One of the main reasons of the explorations was to get gold using the camel to transport it.

The explorations near the African western and eastern coasts were supported by Roman ships and deeply related to the naval commerce (mainly toward the Indian Ocean).
The Romans also organized several explorations into Northern Europe, and explored as far as China in Asia.

;30 BC – 640 AD: With the acquisition of Ptolemaic Egypt, the Romans begin trading with India. The Romans now have a direct connection to the spice trade, which the Egyptians had established beginning in 118 BC.

;100–166 AD: Sino-Roman relations begin. Ptolemy writes of the Golden Chersonese (i.e. Malay Peninsula) and the trade port of Kattigara, now identified as Óc Eo in northern Vietnam, then part of Jiaozhou, a province of the Chinese Han Empire. The Chinese historical texts describe Roman embassies, from a land they called ''Daqin''.

;2nd century: Roman traders reach Siam, Cambodia, Sumatra, and Java.

;161: An embassy from Roman Emperor Antoninus Pius or his successor Marcus Aurelius reaches Chinese Emperor Huan of Han at Luoyang.

;226: A Roman diplomat or merchant lands in northern Vietnam and visits Nanjing, China and the court of Sun Quan, ruler of Eastern Wu.

Chinese exploration of Central Asia

During the 2nd century BC, the Han dynasty explored much of the Eastern Northern Hemisphere. Starting in 139 BC, the Han diplomat Zhang Qian traveled west in an unsuccessful attempt to secure an alliance with the Da Yuezhi against the Xiongnu (the Yuezhi had been evicted from Gansu by the Xiongnu in 177 BC); however, Zhang's travels discovered entire countries which the Chinese were unaware of, including the remnants of the conquests of Alexander the Great (r. 336–323 BC). When Zhang returned to China in 125 BC, he reported on his visits to Dayuan