That was a perfect day at Amrum beach.
The sounds in the first part are mine. Directly at the sea, however, there was a strong wind which made audio recording impossible. So I borrowed the sounds of the waves and the seagulls from freesound.org. They are digifishmusic's "Gentle Sea On Flat Beach" and acclivity's "Urban Herring Gulls" - and they sound exactly like what I would have recorded if I had been able to.