Crowd size at the inauguration. Literally Day 1. www.theguardian.com/us-news/2017...

Trump's inauguration crowd: Sean Spicer's claims versus the evidence

White House press secretary’s claim that the media faked low attendance does not stack up against photos, video and public transport figures

Also a lot of the small crowd of people at Trump's inauguration were there protesting him. We had trouble getting photos that didn't include protest signs!

I went to a presentation a few years ago by a British academic who is known for his expertise in crowd size prediction and measurement. He had been commissioned by US press (possibly NYT) to estimate this. He ended up getting named and vilified, and received death threats