Wide Leg Pants was first popular in
1970s
In the mid-1970s, bell-bottoms became fashionable for both men and women in Europe and North America. Often made of denim, they flared out from the bottom of the calf, and had slightly curved hems and a circumference of 18 inches (46 cm) at the bottom of each leg opening. They were usually worn with Cuban-heeled shoes, clogs, or Chelsea boots. Bell-bottoms are mentioned in the popular 1971 music single "Bell Bottom Blues" by blues-rock group Derek and the Dominos.
In the 1970s, bell-bottoms moved back into mainstream fashion; Sonny and Cher helped popularize bell-bottoms in the US by wearing them on their popular television show. The pants were typically flared from the knee down, with bottom leg openings of up to twenty-six inches. Made from denim, bright cotton and satin polyester, they were so popular that they became a symbol of the outlandish and colorful style of the decade.
Source:https://en.wikipedia.org/wiki/Bell-bottoms
