My second Bivy Bag Night as part of my Great Britain Extreme Point challenge was spent at Holme Fen, Huntingdonshire on 26/27 August 2011. Holme Fen at 3m is the lowest point of Great Britain.
Over many years drainage of the surrounding farm land has caused the peat to shrink. This shrinkage has been recorded by the Holme Fen Post (see above), a cast-iron column that was sunk into the fen in 1852. The column (believed to have been part of the Crystal Palace) was sunk till its top was level with the peat surface, but it now rises some four m above ground level.