Cromer Windmill - Hertfordshire's sole surviving windmill and a grade II* listed building dates from 1681, as determined by a dendrochronological survey conducted in 1998. It stands on an artificial mound just outside Cromer, near Ardeley, in which parish a windmill has stood for nearly 800 years. Cromer Windmill is open 2.30pm to 5.00pm on Sundays and the second and fourth Saturdays from mid-May until mid-September and also the late Spring Bank Holiday Monday and the August Bank Holiday Monday; groups at other times by appointment.