Classic hippie wear. Bellbottoms hit the mainstream scene in the 60's. The great style hugs the thighs wonderfully and flair at the knee. This flair can be very large, depending on the pant.

Originally, according to Wikipedia, bellbottoms originated in the 19th century for naval soldiers."These "bell-bottoms" were often just very wide-legged trousers, unlike modern versions cut with a distinct bell." Stylish wasn't the desire but they were comfortable and easy to move in.

In the 60's the trend spread. Many women picked up on the new bellbottoms trend and the men weren't too far behind. By the late 60's the bellbottom had both male and female fans. The gender neutral style allowed everyone to be comfortable and hip. 

The style was made popular by many celebrities in the 1960's and 1970's. Seen first the 1964 concert film The T.A.M.I. Show, Toni Basil wears them as a go-go dancer. Also, on the Sonny and Cher Variety Show, the trend reached it's peak. Bellbottoms also drew homage in a song Bellbottom Bluesoriginally recorded by Derek and Domino (later remade by Eric Clapton). Soon enough, people were dying to get their hands on these adorable pants.