Perhaps the most remote-feeling of all our suggested rambles, the London Wildlife Trust's oldest nature reserve forms part of the largest remaining tract of the old Great North Wood, a natural oak woodland that dates back to the 13th century. Picking up the Cox's Path by crossing an ornamental footbridge over an old railway track will bring you past some breathtaking remnants of Victorian gardens and those aforementioned ancient oak trees. Take it slow and you may even spot a woodpecker or one of the other 200 species that call this reserve home.