Until August 15, Afghanistan was officially an Islamic republic.
The situation changed almost overnight, as Taliban militants entered the presidential palace in Kabul and declared the re-establishment of the Islamic Emirate of Afghanistan, reviving the title of the country when the group ruled most of its territory between 1996 and 2001.
Here are some quick facts about the mountainous Central Asian nation.
From monarchy to militias
Afghanistan became an independent country in 1919 after signing the Treaty of Rawalpindi with the British government. This allowed it to regain control over its foreign affairs under King Amanullah Khan's rule.
In 1973, Afghanistan took on the republic title after Mohammed Daoud Khan deposed his cousin, King Mohammad Zahir Shah, in a coup d'etat.
The official name changed slightly in 1978 when the Communist People's Democratic Party of Afghanistan took power and the country became the People's Democratic Republic of Afghanistan.
Russian forces invaded a year later to support an allied Communist faction amid growing public unrest – the beginnings of what would become a large-scale national uprising.
The situation descended into a decade of bloodshed where an internationally supported resistance force, the Afghan Mujahideen, fought the Soviets until they were forced to leave the country, amid an economic crisis in Russia.
That conflict would leave much of the country in ruins and claim an estimated one million lives.
After the collapse of the Soviet Union in 1991, Russia's Afghan ally President Mohammad Najibullah clung onto power, during a chaotic civil war which was exacerbated by ethnic and sectarian tensions.
The war settled into a stalemate with the Taliban – a movement dominated by ethnic Pashtuns, taking control of Kabul in 1996 and declaring the Islamic Emirate of Afghanistan.
Their reign was characterised by draconian rules on what people could do in society, for example, music and television were forbidden.
The Taliban rulers were toppled in 2001 by a US-led international coalition, backed by allies in the north of the country who, in the main, were not ethnically Pashtun. The Northern Alliance fighters were predominantly Uzbeks, Tajiks and the Hazara minority.
While the Western-backed Northern Alliance triumphed in 2001, it was not until 2004 when a new constitution was agreed upon that Afghanistan once more became an Islamic republic.
Terrain: Afghanistan is famous for its fearsome, rugged mountains that have provided refuge for rebels fighting foreign invaders for centuries. High altitudes and rocky terrain make it difficult for ground forces but the thin air even causes problems for helicopters.
Any soldiers who face this environment can expect bitter conditions in the winter.
In the country's east, dense pine forests cover the hills of Paktia, Paktika, Khost, Kunar and Nuristan.
But much of the south, including provinces such as Kandahar and Helmand, is very arid and temperatures in the summer can rise above 40°C. While the country is ringed by a massive highway built by the Soviets and Americans, known as Highway 1, many rural communities are unreachable due to poor road quality.
Taken together, these extreme terrain conditions help explain why the country has been known as "the Graveyard of Empires."
Population: Afghanistan is home to some 38 million people, according to the latest data. Children 14 years and younger make up just over 40 per cent of its population.
Education: Only about 10 per cent of those eligible make it to tertiary education, the majority of whom are men, UN statistics showed in 2018.
Ethnic diversity: Pashtuns make up the majority of Afghanistan's ethnic demographic followed by Tajiks, Hazaras, Aimaks, Turkmen and Balochs respectively.
Currency: Afghani (the people are Afghans). One Afghani is roughly 0.012 US Dollars.
Leadership: Up until Sunday, August 16, Afghanistan's President Ashraf Ghani ruled over the country. But, after the Taliban surrounded the capital, Kabul, the group said a "peaceful transition" of power would come within days.
Official language: Dari (Afghan Persian) and Pashtu