Geography and climate. Burma is an up-and-down country sandwiched between India and Bangladesh in the northwest, China and Laos in the east, and Malaya in the south. The Andaman Sea and the Bay of Bengal create long seaboards.
Just as Egypt is “the gift of the Nile,” Burma is “the gift of the Irrawaddy.” Burma’s chief river runs most of the length of the country through a wide, lush valley. Encircling that valley to west, east, and north are ranges of hills and increasingly rugged mountains.
Burma is in Monsoon Asia: there is a wet season and a dry season (October-May); it’s mostly hot and sometimes steamy. For Western travelers, health dangers abound.
The history that matters. Burma began as a series of city-states in and around the Irrawaddy River valley between 200 and 100 BC. Larger kingdoms rose and fell through the 800s AD. All the while, new ethnic groups immigrated from China and India. Then, during what Europeans would call the High Middle Ages (c. 1000-1500 AD), a succession of still bigger kingdoms emerged to engulf many of the territories surrounding the Irrawaddy valley; and first Buddhism, then Islam spread from India. All this created an ethnically and religiously diverse Burma. From the late 1600s to the early 1800s, a series of empires and kingdoms sought to expand the boundaries of Burma and to impose strong central government on outlying ethnic communities.
This worked pretty well until an expanding Burma collided with an expanding British Empire in India. Three Anglo-Burmese Wars (1824-1885) ended in British rule over Burma.
British rule increased the Western impact on the country: Buddhism was disestablished as the state religion; secular schools—largely staffed by Christian missionaries—were created; a fleet of riverboats and ferries sailed the rivers; and a railroad ran the length of the great central valley. Furthermore, many new immigrants—Indians—settled in Burma, while the mixed race “Anglo-Burmese” later became an important sub-group. The British administration granted enlarged autonomy to the “tribal” areas containing ethnic minorities. By the early 20th Century, Burma had become a remarkably diverse multi-ethnic community.
Naturally, British rule inspired a student-led nationalist movement. Minor British concessions failed to appease nationalist demands before the Second World War. The Burmese ethnic groups had composed their differences—for the moment—in a 1944 conference. A war-exhausted Britain granted independence in 1948.
When the civilian government failed to squash demands from the ethnic minorities for greater self-government, the army overthrew the government (1962), then later changed the country’s name to Myanmar. Burma has been a military dictatorship ever since. The generals have wrecked the economy through socialist-inspired policies incompetently applied. They haven’t done much better at either defeating or reconciling the ethnic minorities. A host of ethnic “National Armies” dominate much of the country. The recent persecution of the Muslim Rohingyas has attracted much attention, Burma/Myanmar is a cauldron of conflicts. Prominent among the rebellious areas is the Shan State.
 See: https://www.lonelyplanet.com/myanmar-burma
 See: https://en.wikipedia.org/wiki/List_of_ethnic_groups_in_Myanmar