© David Douglas Duncan, 1957, ‘Picasso que un masque d’Horreur’, Cannes

Some friendships begin under unique circumstances or in extraordinary places: a statement which presumably the American photo journalist David Douglas Duncan and the Spanish painter, sculptor and illustrator Pablo Picasso would subscribe to.

When Duncan first met Picasso in 1956, the latter was sitting in the bathtub, scrubbing himself with a washcloth. This scene, as odd as it was intimate, also offered Duncan the opportunity for his first photograph – in certain ways it laid the foundation for the deep friendship between the two men. Henceforth, the former war photographer visited Picasso at his villa in the south of France and at his studio and was allowed to witness and portray him at work and as a private, withdrawn person.

Picasso’s principle of limiting the number of photographers allowed to take his likeness did not apply to Duncan. Their mutual affection resulted in many personal portraits of the artist and insights into his oeuvre and private life. Above photograph was taken in Cannes in 1957 and shows Picasso posing with naked upper body, a wig and facial mask. The fact that this curious portrait was taken only one year after the two men’s first meeting gives an indication of their intense bond of friendship, which was to last until Picasso’s death in 1973. (+)

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© David Douglas Duncan, ca. 1950, Korean War

"This," Duncan told LIFE.com of a picture made during the fight for Seoul, “is the best picture I made in Korea of civilians — a family running down stairs, a father holding a baby, tanks firing away. Those tanks are taking fire from North Koreans right down the street.”

On the anniversary of the start of that brutal, often savage conflict, LIFE.com presents a gallery of Duncan’s celebrated pictures from America’s “Forgotten War.”

From the hellish heat of summer to the arctic freeze of winter, Duncan traveled with Marines, documenting the grinding, torturous lives they led — and that troops everywhere have always led — in war zones the world over.

While recalling the unspeakable violence and gnawing deprivation (no warmth in winter, no relief from the heat in summer, hunger all the time) of those years, Duncan makes a point of praising the Americans’ South Korean allies. "The thing that comes to mind right away, right now, when looking at these pictures again," Duncan says, "is that at no time — at no time — did any Marine feel he had to look around to see what the South Koreans were doing behind him. The Marines in Korea never feared ‘friendly fire’ or artillery coming from the South Koreans — from their allies — like they did later in Vietnam, fighting with the South Vietnamese. The Koreans could be trusted."

The Korean War lasted for roughly three years, from June 25, 1950 — when North Korea invaded the South — until 1953, when the United Nations Command, the North Korean People’s Army and the Chinese People’s Volunteers signed an armistice agreement. However, the South Korean president, Syngman Rhee, refused to sign the document — meaning that, technically, North and South Korea have been at war for the past six decades. (read more)

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© David Douglas Duncan, 1962, Pablo Picasso at Vauvenargues

“People want to find a meaning in everything and everyone. That’s the disease of our age…” (Pablo Picasso)

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