I have lots of photographs with a background of blue sky, but thought something blue itself would be better. This is actually the door to the work place of the Park staff - bolted and barred for the weekend. With a lot of expensive machinery in there, it makes sense.
The second photograph is of a Grape Hyacinth (Muscari). I have loads of them in a low brick wall, and they cheer me up every year with the very clear blue of their tiny flowers. They are not out yet, but I can imagine them with this photo and hope it won't be too long before they arrive!