Host Julie Chen congratulates Josh Martinez, who wins the final HOH competition of the 19th season of "Big Brother."Sonja Flemming/CBS
- CBS's "Big Brother" has been on the air for 20 years.
- "Big Brother" also has a "Celebrity Big Brother" spin-off in the US and UK.
- There are almost 100 cameras watching every houseguest, including a few cameras in the bathroom.
- The longest competition lasted for more than half a day.
Ever since "Big Brother" first locked away a group of competitors — called houseguests — in a house for the summer and called it reality TV, people have been tuning in to see all the drama unfold in real time.
Airing three times a week on TV, the CBS show is on all of the time thanks to a set of cameras and microphones that pick up contestant behavior 24 hours a day, seven days a week, and stream it live to audiences online.
Fans can watch the houseguests eat, cook, and sleep — and strategize, of course. This is a competition show, after all, and the prize is $500,000.
But with 20 years and over 20 seasons under its belt, even the biggest of superfans don't know everything there is to know about this show.
Here are 21 surprising things you probably didn't know about this reality-TV staple.