This is a video of paintings by Piet Mondriaan in the Kröller-Müller Museum in the Netherlands.
From Dutch news agency ANP:
AMSTERDAM – During a valuation in France, three unknown paintings by Piet Mondriaan have been discovered.
These oil paintings are not in the Mondriaan catalogue from 1998. …
These three paintings are ‘Haystack behind a row of trees’, ‘Iris against a red background’ and ‘Farm surrounded by trees’. …
The paintings are from 1902 – 1909 when Mondriaan still worked in a naturalist style.
Later, he would become internationally famous as an abstract painter.