A ha-ha looks like a ditch that has a vertical brick retaining wall on one side which is unseen from the main house and gardens, the ditch is usually turf and slopes back up to ground level.  The ha-ha is situated at the edge of the garden or pleasure grounds that surround the main house, the main purpose is to provide uninterrupted views of the estate or parklands and distant coutryside views.

Visually from the house or pleasure grounds there are seamless views however it also stops livestock such as cows, deer or sheep from entering and destroying the gardens yet allows them close enough to graze and been seen.

The ha-ha is said to have been invented by Charles Bridgeman but is an essential component of the 'Capability' Brown vistas.