The London Olympics Opening Ceremony will look to dazzle and amaze a worldwide audience Friday night. Those behind the show say it will be uniquely British, following a final walkthrough, held in front of thousands at London Olympic Stadium.

62,000 people were lucky enough to watch a dress rehearsal of Danny Boyle’s extravagant opening ceremony, which reportedly cost 27 million pounds. The Stratford subway station faced its first Olympic-sized challenge, with spectators flocking to the stadium.

The security level was also raised to the highest alert, as officials worked to keep any potential threats in check. Some of the ceremony’s highlights include a scene depicting traditional countryside cottages standing alongside a mining wheel, harking back to Britain’s industrial heritage.

But with the main contents of the 3-hour extravaganza are still a complete mystery, leaving observers with a big mystery about how the final show will come together.