First of all I would check the Natural History Museum in London. They have a Mammoth skeleton hidden behind a Whale in the mammals section. They also have sabre tooth (Smilodon) somewhere around.
The second best address, would be the "Muséum national d'Histoire Naturelle" in Paris. It has a HUGE hall full of skeletons, with several Mammoth models.
There are at least 2 complete Mammoth Skeleton in the back of the hall:
Then there is the "Naturhistorische Museum" in Vienna, Austria (Museum for nature history). It has a quite extensive collection of complete skeletons. They do not seem to have a Mammoth skeleton in particular but instead a model of a complete animal, with fur etc.
Here is the similodon skeleton from there: