What is the most expensive world record ever set, and what did it cost to accomplish?

The most expensive world record ever set is for the highest-grossing movie of all time, and it was accomplished by James Cameron's 'Avatar' in 2009. The film grossed a staggering $2.79 billion worldwide, making it the first movie to ever cross the $2 billion mark.

The cost to accomplish this record-breaking achievement was estimated to be around $500 million, which includes the production and marketing costs. The movie's groundbreaking visual effects and 3D technology were the primary reasons for its success. It took Cameron over a decade to develop the technology required to create the film, which involved developing new cameras and software specifically for the project.

The success of 'Avatar' has led to the announcement of several sequels, with the first one set to release in 2022. It remains to be seen whether any film will be able to break the record set by 'Avatar', but the film's impact on the film industry is undeniable.