What was the largest fillibuster?

In the American Senate:

Senator James Strom Thurmond (D/R-SC) set a record in 1957 by filibustering the Civil Rights Act of 1957 for 24 hours and 18 minutes, although the bill ultimately passed. Thurmond broke the previous record of 22 hours and 26 minutes which Wayne Morse (I-OR) had established in 1953 protesting the Tidelands Oil legislation.