What are some of the famous fences? The Aintree fences are not quite as perilous as they were once upon a time after a series of alterations. However, they are still the most notorious obstacles in the business and enough to make the palms of any jockey sweat. Becher's Brook: The sixth and 22nd fence in the race may not be the biggest, but it's difficulty comes from the fact the landing side is 10 inches lower than the take off side. Named after Captain Martin Becher, a jockey who fell at this stage and hid in the brook to avoid injury.