Spookily quiet! Paseo de La Castellana - no traffic and no people - weird!

It doesn't seem to be a Covid thing. On some Sundays sections of this north-south main Madrid axis are closed. I presume for demonstrations or just for the public to enjoy on foot, on bikes, on scooters, roller skates, etc. But honestly I don't know why! However,today it was blocked off along very long sections and there was absolutely no-one around. It's like seeing Oxford Street or the Champs Elysées on a Sunday afternoon without a soul. Unthinkable! And I'm still puzzled! If Prez T was paying a visit to Madrid I could understand it; no crowds would show so no security would be required!