BBC.
The discovery of fossilised remains belonging to the world's largest snake has been reported in Nature journal.
Titanoboa was 13m (42ft) long - about the length of a bus - and lived in the rainforest of north-east Colombia 58-60 million years ago.
The snake was so wide it would have reached up to a person's hips, say researchers, who have estimated that it weighed more than a tonne.