Yom Kippur War

The Yom Kippur War (also known as the Ramadan War and the October War) was a war between Israel and a group of Arab countries led by Egypt and Syria. The war took place from October 6-24, 1973. The war began on the Jewish day of repentance of Yom Kippur in 1973, and it happened during the Muslim month of Ramadan where the army was fasting. The attack by Egypt and Syria was a surprise to Israel after Israel conquered the Sinai peninsula and the Golan Heights from Egypt in 1967. Egypt's army entered the Sinai Peninsula to retrieve their land from Israel.
Background.
The Sinai and the Golan Heights previously belonged to Egypt and Syria, but they were occupied by Israel since 1967 during the Six Day War. Syria's aim of the war was to liberate all of the Golan Heights.
Battles.
During the first few days of the war, Egypt and Syria scored victories. Israel was shocked by the attack and was about to be defeated. The first Israeli counterattacks failed against both Egypt and Syria. However, Israeli attacks later repelled the Syrian forces and pushed them back. The Iraqi army joined the war with Syria and the Israeli army stopped advancing.
On the Egyptian front, Israel's attacks against Syria had served as a 'distraction' against the Egyptian offense. This allowed the Egyptian army to dig deeper into Sinai, around 12 km, an extra 2 km to the original 10 km plan. Israel feared a massive military defeat and so called on America for aid. Initially, America refused so Israel threatened to use its nuclear weapons, this threat was enough to persuade President Richard Nixon to send aid to Israel. America conducted "Operation Nickel Grass", which gave Israel a resupply of 22,000 tons of military equipment and ammunition, as a response to the parallel Soviet supply operation, in which 15,000 tons of equipment were airlifted, and 63,000 tons of equipment were sealifted. This vital to Israel and it allowed Israel to continue fighting despite being heavily outnumbered. Henry Kissinger, However, this was later denied.
The Egyptian army crossed the Suez Canal on October 6 and destroyed the Israeli defenses and forts on the other side. Israel tried for the next few days to defeat the Egyptians and push them back behind the canal. However the Israelis could not push them back, so they lured the Egyptian army deeper into the Sinai, in an effort to encircle them. The United States of America started sending ammunition and weapons to Israel using airplanes to help the Israeli army win the war in Operation Nickel Grass. Syria soon pleaded Egypt to attack Israel to lessen the pressure on it. On October 14, Egypt attacked again, trying to advance even more into the Sinai, after Syria reported a false victory against Israel in the northen front. This led to the Egyptians pushing forward into Israeli controlled territory without any air cover, allowing Israel to encircle the entire 20,000 men strong Egyptian 3rd army, cutting it off of any supplies, via the invasion of mainland Egypt by Israeli forces. Egypt tried stopping this invasion with its elite 25th Armored Brigade with the most advanced tanks of the time, but fell into an Israeli tank ambush and was completely destroyed.
After this, the Israelis attacked again, and were pushing into mainland Egypt. After heavy fighting, they crossed the canal at its center, between two Egyptian armies. They advanced north and south until the reached the city of Suez in the south, and trapped the Egytian 3rd Army in the eastern side of the cannal, in the Sinai. Saddat, worried by the encirclement of his 3rd Army, which if collapsed could lead to the collapse of the 2nd Egyptian Army and the war as a whole, called Brezhnev, urging him to stop the war. Brezhnev brought in air-deployable battallions from Europe, and threatened the US to quickly stop the war. The Israelis tried to capture Suez, but they were defeated. They also failed to advance north. They reached an area 101 kilometers from Cairo, the capital of Egypt, and captured 1600 square kilometers in mainland Egypt.
UN resolution.
Saddat, worried by the encirclement of his 3rd Army, which if collapsed could lead to the collapse of the 2nd Egyptian Army and the war as a whole, called Brezhnev, urging him to stop the war. Brezhnev brought in air-deployable battallions from Europe, and threatened the US to quickly stop the war.
The United Nations passed a resolution in the security council that asked all the countries to bring a temporary stop to the war (called a 'ceasefire'). The Arab countries and Israel agreed. However the ceasefire failed when the Israeli army advanced south to reach Suez. After this, the Soviet leader, Leonid Brezhnev, said to the US president that if the US did not send troops that he would send Soviet troops to the area. This was believed to be a threat and the United States put their military on full nuclear alert. Because of this tension between the United States and the Soviets, Israel agreed to a ceasefire, and the war ended. It was the closest the two superpowers, the United States and the Soviet Union, had been to nuclear war (and World War III) since the Cuban Missile Crisis of the 1960s.
End.
The war ended on October 26, 1973. After the war, Egypt and Israel negotiated. They reached an agreement to separate their forces. The agreement led to Israel withdrawing from the Suez Canal only 6 years after the end war, due to the 1979 Camp David peace accords. 
Israel also held negotiations with Syria and agreed to withdraw from the places the captured in Syria, but they stayed in the Golan Heights. Egypt and Israel kept their negotiations, and in 1979 they signed the Egypt–Israel Peace Treaty. The treaty brought peace between Israel and Egypt, and Israel withdrawn from the whole Sinai and returned it to Egypt. The treaty still holds to this day. The Egyptians celebrate victory in this day due to their successful attack at the start of the war, despite clear tactical and strategic shortcomings and failures that happened throughout the rest of the war which led to their defeat. Syrians on the other hand do not like to talk about the war as much of it was seen as a defeat rather than a victory or stalemate.