1. Bellbottoms reached their height (or should we say width?) in 1975.
2. Bellbottoms have their origins in sailor pants, a style which was also fashionable in the 1930s.
3. For sailing folk, the flared legs made it easy to put boots on and to roll up the legs in case of high water. Both features are, of course, still useful to us today, sailors or not. ETA: Ladykatza noted that the main reason for the flared legs was that if a sailor ever found himself overboard, the pants could quickly be removed, tied off at the ends, and used as a flotation device. I knew bellbottoms were a fashion statement; I didn't know they were a safety device!
4. I wasn't able to find a concensus on the definition of bellbottoms other than that the hem is flared. How much do they flare? Are they fitted at the waist and hips, flaring below the knee (hip-huggers)? Or are they wide-legged? The choice is yours.
5. Bellbottoms came in a WIDE variety of fabrics.
6. Despite their obtrusive nature, bellbottoms need NOT be made in unobtrusive fabric!
Seersucker: an excellent choice for picnics.
More double knit: a matching cardigan and front leg seams add that extra touch.