Who can figure this one out first?
Imagine a place called Metro City. It's right next to this large mountain called Mt. Yama. It has not rained in Metro City or on Mt. Yama in three days.
Two days ago, a group of thieves broke into, hotwired, and drove off in a black van. The police haven't gotten around to thoroughly investigating the theft yet, and as such they don't know where the thieves are hiding out.
This morning, you and your friend, Bob, wake up in a hotel, eat some breakfast, and then go sightseeing, as you're both from elsewhere and you hear Metro City has some great tourist spots.
Then, out of nowhere, the thieves abduct Bob and drive away in that same black van which was stolen two days prior.
You aren't able to provide any description of the culprits, as they were wearing ski masks and thick suits and gloves and stuff. However, you notice one thing: the windshield and windows of the black van were wet, whereas the rest of the car was dry.
Based on this one thing, you, being a college detective, deduce that the criminals' hideout is high up on Mt. Yama. How did you come to this conclusion?