This is not a typical garden wall. It is a brick “retaining wall” which is 3 metres high. On the boundary between your house and your neighbour further up the hill.
Such walls restrain a considerable amount of weight and pressure behind them. If they fail in whole or in part they can be extremely costly to repair or rebuild.
Regular maintenance should not therefore be neglected. Before you buy your new home make sure you know who owns the wall. You or your neighbour!