Paleontologists regularly found small black stones with lots of scratches near many Neanderthal settlements, the chemical composition of these stones was manganese oxide.
The paleontologists were puzzled about this, until they found out that if you rub those stones together, it works as a catalyst: it lowers the combustion temperature of wood from 350 degrees celsius to 250 degrees celsius and also speeds up the rate of burning. This hints at an unknown Neanderthal technology for making fire.
Old Neanderthal arceologichal findings on far to sea islands indicates that neanderthals made canoes over 100 000 years ago, or that they were exceptionally good swimmers.