The word "police" I am struggling with the use of the word "police", as far as I know it is uncountable and generally works as plural. In case I want to refer to different individuals I can make it countable by adding officer\s or man\men etc; bu what about police as single public institution ? Thank you for your help, it would be of great advantage to me if you could also make examples !

German series and music

Book for starting studying Spanish I studied Spanish in secondary school for three years, lately I have been thinking about starting studying it but more seriously. I have totally removed everything I knew, but since my best friend is Spanish I could practice it with him and make rapid progress. I don’t know if it is better to buy an A2 level book (for Dele) or just a general volume. Thanks for your attention.

Netflix lovers let's be useful to each other !

I need suggestions on tv-series that could help me to start improving my English again. I am an advanced student, therefore you are completely free to recommend even something a bit complex. 

PS: I have already watched "Sherlock", "Downton Abbey", "The Crown" ( I precise it because they are often suggested to students )