Fossilized remains of world's largest snake:

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 team of researchers led by Jason Head, from the University of Toronto at Mississauga, Canada, used a known mathematical relationship between the size of vertebrae and the length of the body in living snakes to estimate the size of the ancient animal.

Named Titanoboa cerrejonensis by its discoverers, the beast's 13m-long body and 1,140kg (2,500lb) weight make it the largest snake on record.

"At its greatest width, the snake would have come up to about your hips. The size is pretty amazing," said co-author P David Polly, from Indiana University in Bloomington, US.

Be sure to read the article and see the photo of this thing's vertebra next to one from an anaconda. Damn!

Cronaca beat me to it.

Update: Via Tet Zoo, an excellent post on Titanoboa, including this observation:

Large population surveys of reticulated pythons have failed to find individuals longer than 6 metres. By contrast, Head's team analysed vertebrae from eight different specimens of Titanoboa and found that all of them were roughly the same size. A length of 13 metres was fairly ordinary for this extraordinary serpent.