What is the fine-grained topic of the following text: Over 100 classic vehicles of all types - car, motorcycles, commercial vehicles and even a six-wheeled Range Rover fire engine - turned up for the occasion and made for a spectacular sight in the sunshine, as HRH The Duke of Kent flagged them off for the start of the Classic 300, an 18 mile drive around Great Windsor Park. Only return the topic.
Classic vehicle event in Great Windsor Park