Soviet troops invaded Afghanistan on 24 December 1979, launching a war which lasted a decade. The BBC has spoken to people on both sides about a conflict which marked their lives.
Omar Nessar was a schoolboy from an academic family in Kabul when Soviet forces invaded and he vividly remembers how the war haunted his childhood. Now living in Moscow, he edits a website serving Russia's large Afghan community - afghanistan.ru.
I was about six or seven and I remember it was the start of the new school year and I was astonished to see a portrait on the first page of the schoolbooks of a man I had never heard of before: [short-lived Afghan President] Nur Mohammed Taraki.
Omar Nessar is one of 150,000 Afghans living in Russia
One day on my way to school I saw a column of Soviet tanks. Soldiers sat on the turrets smiling at passers-by while children stood looking at them out of curiosity.
That evening, the TV showed people greeting Soviet tanks entering Kabul with flowers. I think many people first reacted to the invasion either positively or neutrally. I remember people saying that the Soviets had come for two or three years, after which they would leave Afghanistan.
My father worked in the education ministry and my mum taught at Kabul University. Like many Afghan families, our relatives ended up on different sides of the front.
While my mum was never a party member most of her relatives held fairly high posts in the party and the government. Father was a rank-and-file member of the [ruling] People's Democratic Party although most of his family joined the mujahideen after the invasion and left for Pakistan.
My father began by believing enthusiastically in the "Revolution" but gradually, like many others, became frustrated at the presence of Soviet advisers in the ministry. I recall how he would come home in the evening and complain that the advisers at times insisted on a say in everything and anything which did not concern them.
I well remember how often the whole family would go out of the city for picnics, like to Paghman or to the country house of our relatives, which the Soviets later turned into an observation post.
After the invasion, I was never back there and I asked my parents for a long time why we never went to my beloved Paghman. They always told me it was too dangerous and I did not understand why.
I have to say that I and many people of my age remember those years with nostalgia because the mujahideen did not meet the hopes of the people after the Soviet withdrawal.
Under the communists, Kabul was a beautiful city with a well-developed infrastructure. Such things as drinking water, 24-hour power supplies, telephones, working schools, universities, hospitals and public transport are now considered a luxury there.
The Russian government's policy towards Afghanistan in the 1990s is inexplicable. We all now know that Moscow even held talks with [pro-Soviet Afghan leader Mohammed] Najibullah's enemies. Russia dug the grave of its own ally.
Many Afghans, former officers and party members, came to Russia in the hope of finding refuge but unfortunately their hopes were not realised and even former senior politicians were left to fend for themselves. But Afghans now living in Russia do not harbour any grudge against the people of Russia.
The vast majority of Afghans living in Moscow believe in Afghanistan's future and are happy, on the whole, with Hamid Karzai's policies. Every week, hundreds of Afghans make use of the restored direct air link between Moscow and Kabul to visit the old country.
Interviewed by Patrick Jackson, BBC News.