It all started when Russian President Vladimir Putin announced a "special military operation" to "demilitarise" and "de-nazify" its neighbouring country and protect Russian speakers in the country.
He had warned the international community against intervening. A full-scale invasion starts with air and missile strikes on several cities.
On Februay 26, the Western countries responded to the invasion of Ukraine and slapped Russia with unprecedented sanctions against Russia and helped Ukraine with military equipment and finance.
A number of Russian banks were banished from the SWIFT interbank system. Air spaces are closed to Russian aircraft and Russia is kicked out of sporting and cultural events.
On February 28, Putin had also ordered the Minister of Defense and the chief of the General Staff to place the Russian Army Deterrence Force on "combat alert".
With his troops quickly getting bogged down, Putin put Russia's nuclear forces on high alert, citing "aggressive" statements by NATO members and the financial sanctions.
During the first peace talks between Kyiv and Moscow, Russia set out its demands, including the recognition of Russian sovereignty over Crimea, the "demilitarisation" and "de-nazification" of the Ukrainian state and the guarantee of its neutrality.
Meanwhile, Ukrainian President Volodymyr Zelensky, who pledged to stay in Kyiv to lead the resistance, appealed for "immediate" EU membership.
This file photo by his Maxar taken and released on March 16, 2022 shows a Russian ground forces deployment near the runway at Kherson Airfield, Kherson, Ukraine.
On March 3, the southern city of Kherson became the first city in Ukraine to fall. Russian troops gain ground in the south in a bid to link up territory held by pro-Russian rebels with the Russian-annexed peninsula of Crimea.
On March 4, Russia enacted a new law punishing "fake news" about what it termed its "special military operation" in Ukraine with jail terms of up to 15 years.
Several international broadcasters suspended their coverage from Russia and an independent Russian radio station and TV channel close down.
NATO also rejected Kyiv's pleas for a no-fly zone over Ukraine.
As the conflict continued to escalate in the early days, civilians tried to leave the country and go someplace safe.
Several attempts to evacuate residents trapped for days without power, water and heat in Mariupol failed in the face of continued shelling.
Ukraine and the UN rejected Moscow's offer to evacuate people to Russia. On March 8, the first humanitarian corridors were set up, allowing thousands of civilians to escape the northeastern city of Sumy and the suburbs of Kyiv.
On March 8, in a bid to starve Moscow of funds for the war, US President Joe Biden announced a ban on US imports of Russian oil and gas. The EU said it will cut its imports of Russian gas by two-thirds.
On March 16, Zelensky compared the invasion by Russia to 9/11 and the Pearl Harbor attack, which forced the United States to get involved in World War II. Meanwhile, Kremlin said the war in Ukraine was "going to plan" amid talk of compromise at peace talks.
During an emotional and impassioned video address to the US Congress, Zelensky said, "In your great history, you have pages that would allow you to understand Ukrainians, understand us now when we need you right now."
"Remember Pearl Harbor. The terrible morning of December 7, 1941, when your sky was black from the planes attacking you," Zelensky said, adding that the attacks on September 11, 2001 "turned your cities, independent territories into battlefields."
The Ukrainian President said that his country is seeing such horrors every day. "Our country experiences the same every day. Right now, every day, every night for three weeks now ... Russia has turned the Ukrainian sky into a source of death of thousands of people," he said.
On March 17, US President Joe Biden branded Putin a "war criminal" following the bombing of a theatre in Mariupol where families were sheltering.
Moscow reacted by saying US-Russia ties are at breaking point.
On March 18, Russia's defence ministry said that they have used its newest Kinzhal hypersonic missiles for the first time in Ukraine on Friday to destroy a weapons storage site in the country's west.
Russia has never before admitted using high-precision weapons in combat. State news agency RIA Novosti said it was the first use of the Kinzhal hypersonic weapons during the conflict in pro-Western Ukraine.
The Russian defence ministry said Saturday, "The Kinzhal aviation missile system with hypersonic aeroballistic missiles destroyed a large underground warehouse containing missiles and aviation ammunition" in the village of Deliatyn in the Ivano-Frankivsk region."
Zelensky appealed for direct talks with Putin. He said he is prepared to discuss the status of Russian-occupied Crimea and two breakaway Moscow-backed regions in eastern Ukraine but that any "compromise" would have to be ratified by Ukrainians in a referendum.
The conflict has killed hundreds of civilians, including dozens of children, and displaced over 10 million people.
According to the office for the UN High Commissioner for Human Rights, at least 953 civilians have been confirmed killed in Ukraine, including 78 children. It warns this is likely an underestimate. (report till March 24).
Moscow has given no toll for casualties among its armed forces since announcing on March 2 that 498 troops had been killed.
Ukraine says around 15,000 Russian soldiers have been killed. Western sources generally give a lower figure but still numbering several thousand.
Kyiv has also not given an update on the number of Ukrainian soldiers killed since Zelensky announced a week ago that around 1,300 were dead.
More than half of all children in Ukraine have been displaced from their homes since Russia launched its full-scale invasion on February 24, the United Nations said on March 24.
"One month of war in Ukraine has led to the displacement of 4.3 million children -- more than half of the country's estimated 7.5 million child population," the UN children's agency Unicef said.
Displaced children make up nearly half of the over 10 million people who have been forced to flee their homes since the invasion began.
More than 1.8 million children have fled Ukraine as refugees, while another 2.5 million are now displaced inside their war-ravaged country, the UN said.