Heritage Open Day: The Wollaton Walled Garden Project, sometimes referred to as the Secret Garden, is a community-led effort, coordinated by Friends of Wollaton Park, to restore the 4-acre walled garden at Wollaton Hall in Nottingham, England Built in the 1780s the walled garden featured heated brick walls and a large conservatory. Later, in the 19th century, the garden was improved with the addition of a complex series of heated glasshouses in which were grown exotic fruits and plants. The garden was sold to the Nottingham City Council, along with Wollaton Hall and the rest of the estate, in 1925. It fell into disuse in the early 1990s and the garden went back to nature.