When you reach the second-floor landing, you'll see various grey cupboard doors. Some of these have spaces behind them containing pipes, so that they can be accessed from anywhere in the house. The hatchway next to the door of the blue bedroom leads to the laundry chute. Leo Kooy, Mr and Mrs Sonneveld's grandson, said this was one of his favourite places to play.

To hear about Leo Kooy, press A.

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