you pull over and walk out to a big rock in a somewhat brushy area to empty your bladder.
At that point you look on the ground behind the rock, there is a bush up against the rock and you notice a black garbage bag between the bush and the rock. Still no traffic coming or going. You grab the bag and open it up, it clearly has a huge amount of of cash in it. You take the bag and return to your car never having seen another car.
Several hours later at home you open the bag and find that there is approx. $1 million in cash.
What do you do?