What is the most expensive world record ever set, and what was the cost of achieving it?

The most expensive world record ever set was achieved by the United Arab Emirates in 2010 when they built the world's largest firework display to celebrate the New Year. The firework display consisted of over 500,000 fireworks and lasted for approximately six minutes.

The total cost of the firework display was estimated to be around $6 million USD. This included the cost of the fireworks themselves, as well as the cost of the equipment and personnel needed to set them off.

The firework display was set off from 400 different locations across Dubai, and was watched by an estimated 1.7 million people who gathered in various locations throughout the city to watch the spectacle.

The achievement of this world record was a significant accomplishment for the United Arab Emirates and helped to showcase the country's commitment to innovation and extravagance.