Puzzle

This puzzle, based on one found in Martin Gardner’s My Best Mathematical and Logic Puzzles, asks you to evenly divide an irregular shape.

An old farmer in Seedonia was getting ready to retire.  He wanted to pass his farm on to his children with half going to his son and the other half to his daughter.  Here’s a map of the farm, which is the pale green area.

How can he draw a line to divide the farm so that the two regions are equal in area? The line does not have to be straight, but it must be one continuous line.