Friday open thread: contrasts

It's school holidays in my part of the world, and as I've been out and about a lot more than usual, the profound effect this has in various physical spaces is incredible. A short list:

Trains to and from Cambridge for work have been half empty, whereas normally I'm fighting for a seat in a heaving crush of people, especially in the afternoon

The footpath when I walk to and from work is completely empty, whereas normally I'm navigating around a seething mass of secondary school students

The roads in central Cambridge are completely empty, whereas normally they're gridlock

My bus ride home today (I caught the bus instead of the train) was in constant motion instead of being stuck in crawling gridlocked traffic

Most astonishingly, the swimming pool where I do laps four mornings a week has also been half full each time, even though my fellow swimmers are not school-age children, but rather other adults — most of them retirement-age

In other words, the contrast between life during school holidays and life ordinarily is stark, and immediately visible. It's what's inspired my prompt this week: can you think of a situation of similarly stark, concrete contrasts?