Some fantastic news like the ones of Venice are only partly true. The water is much brighter mainly because the are no gondels / boats in the canal. The dolphins are no exception. It’s true that the air pollution is way less with so much people at home and industries that lay down. Please check if you’re source is thrust-worthy, especially if its amazing, before you post it here.
In the Netherlands all festivities are cancelled until the first of June. Including Eurovision Song contest, a mass spectacle they do every year with Easter, liberation festivals 75 years after World War II, Kings day festivals, big music Festivals like Pink pop, concert at sea, Paul McCartney in Nijmegen park, etc. But also all the smaller theater and music performances. There is no audience on tv shows. All gatherings where its not possible to keep at leat 1.5 meters distance are forbidden.