* World War I: Escher was drafted into the Dutch military during World War I and served for three years. He was stationed in the Netherlands, but he also saw combat in France. The war had a profound impact on Escher, both personally and artistically. He witnessed the horrors of war firsthand, and he lost many of his friends and fellow soldiers. The war also led to a period of great social and political upheaval in Europe, which influenced Escher's art.
* The rise of fascism: In the 1930s, fascism began to rise in Europe. Escher was deeply opposed to fascism, and he expressed his opposition in his art. His works from this period often contain anti-war and anti-fascist imagery.
* World War II: Escher lived in the Netherlands during World War II. The Netherlands was occupied by Germany, and Escher's art was banned by the Nazis. Despite the challenges, Escher continued to create art, and he produced some of his most famous works during this period.
Art movements:
* Cubism: Cubism was an early 20th-century art movement that broke down objects into their geometric shapes. Escher was influenced by Cubism, and he used its principles in his own art.
* Surrealism: Surrealism was an art movement that emerged in the 1920s. Surrealists sought to create art that was dreamlike and irrational. Escher was influenced by Surrealism, and he incorporated its elements into his own art.
* Mathematical art: Mathematical art is a genre of art that uses mathematical concepts and principles. Escher was a mathematician as well as an artist, and he created many works of mathematical art. His mathematical art is often based on tessellations, which are patterns that can be repeated without gaps or overlaps.