Short answers, pulled from the story.
Nicholas Roerich produced over 7,000 paintings across his career. His canvases are held in museums across Russia, India, Bulgaria, Serbia, Latvia, and the United States, with a significant collection at the Nicholas Roerich Museum in New York City.
The Roerich Pact is an international treaty for the protection of cultural property, signed on the 15th of April 1935 at the White House by the United States and the twenty other nations of the Pan-American Union. It was the result of Roerich's Banner of Peace movement, which he conceived as a Red Cross equivalent for art and culture.
Between the summer of 1927 and June 1928, the Roerich Asian Expedition was detained by Tibetan authorities for five months despite holding Tibetan passports. The party was held in tents in sub-zero conditions with meagre rations, and five expedition members died before authorities allowed them to leave in March 1928.
Roerich designed the costumes and sets for the 1913 premiere of Igor Stravinsky's The Rite of Spring, staged by Sergei Diaghilev's Ballets Russes. The production is considered one of his best-known theatrical works and one of the landmark events of early Modernist art.
Agni Yoga is a neo-theosophical system of mysticism founded by Nicholas Roerich and his wife Helena Roerich in London in March 1920. Also called "the Living Ethics," it combines elements of Western and Eastern thought, religion, and philosophy, and forms the doctrinal basis of the broader movement known as Roerichism.
In June 2013, during Russian Art Week in London, Roerich's Madonna Laboris sold at Bonhams for £7,881,250, including the buyer's premium. The sale made it the most valuable painting ever sold at a Russian art auction.