The "Mountain or Valley?" illusion makes our brains turn valleys inside out. But inside-out valleys are a real thing, both on Earth and on...

Get your FREE 2-month Skillshare trialef='http://skl.sh/minuteearth2' target='_blank' rel='nofollow'>trial The "Mountain or Valley?" illusion makes our brains turn valleys inside out. But inside-out valleys are a real thing, both on...