Almost a quarter of a million people from all over the country are set to visit the Great Dorset Steam Fair over the 5 days.
The annual event in Tarrant Hinton showcases a range of steam-powered vehicles and machinery.
The site spans more than 600 acres.
Organisers say this makes it one of Europe’s largest outdoor event locations.
As well as machinery, there is also a display of camper vans and other vehicles.
One of the highlights of this year's fair is a display commemorating the First World War centenary.
The exhibit includes a replica trench and vehicles.
The fair also features 6 stages around the site hosting live shows and music.
Food is being sold at an indoor court holding hundreds of stalls.
The fair is taking place for the 49th year.
The Great Dorset Steam Fair concludes on Monday evening.