Blue whales are the largest animals ever to live on our planet, and they can reach mind-boggling dimensions. Some of these marine mammals can be up to 100 feet long and upwards of 200 tons. Their skeletons can weigh 18 tons, with their skull alone coming in at almost a fourth of the whole weight.

The Natural History Museum in London houses a proud specimen of a blue whale skeleton that spans 25 meters. How did conservators get the enormous skull through the Victorian doors? The team went on a mission to remove the front doors altogether. Head of Conservation Lorraine Cornish said that “everyone breathed a collective sigh of relief once it was safely delivered.”