In the southern Dutch town of Valkenswaard strange sounds were heard coming from the sky. Roy van Zon, a resident of Valkenswaard, recorded the sounds that appeared in the evening hours of December 9th and 10th. The video can be seen below:

On van Zon's Facebook page, others in the area wrote they also heard the sounds and one other person also recorded the sounds and posted it in the comments section. In a live radio interview with Radio 538, van Zon said: "I received messages from people saying that I edited this, but I didn't do that. I'm glad I wasn't the only one who heard these sounds, as I thought I was going crazy." In another radio interview, with Qmusic this time, van Zon notes that he heard the sounds on Monday for the first time, and on Tuesday evening for the second time.

The two original videos van Zon posted on his Facebook page are as follows:

On Monday December 9th:

On Tuesday December 10th:

A crane operator told Dutch news outlet Omroep Brabant that the sounds could have been coming from a crane, or the safety break of a crane, that was moved by high winds. However, other crane operators didn't recognize these sounds.

In the following video, the strange sky sounds heard in Valkenswaard were compared to the strange sky sounds heard in the Dutch city of Gouda in 2016, and sound similar:

The full video of the strange sky sounds heard in Gouda in 2016 can be seen here.