Sometimes films require more than small scale miniatures in order to make certain special effects look convincing on camera. One of the biggest problems with miniatures is that they can't effectively simulate things like weight and gravitational pull. There is also a big problem when water comes into play. If for example you want to drown a model miniature of a building that has been built at 1:50 scale, the size of the droplets are going to come across on camera as being enlarged. One way to deal with this problem is to build giant miniatures.
This was the method used for filming certain scenes in Titanic that required a lot of action with water. One of the larger models was built at 45 feet long!
Another film that utilised these 'bigatures' was The Lord of the Rings. WETA workshop that worked on the film made huge miniatures of some of the locations, like the one below, with a very high level of detail. This was because they couldn't create the locations in a full size set and they didn't want to opt for CGI for various reasons.