A mile south of the village of Llanwrthyl in the Wye Valley is the impressive Doldowlod House. This fine house and its estate were purchased by the inventor James Watt - 1736 to 1819, perhaps best known for the unit of power measure named after him - late in his life, and while it was in his ownership he made many improvements to it. Doldowlod House is still owned by his descendants, the Gibson-Watt family.