The most visited paid attraction in Ireland occupies the old fermentation building at St James's Gate, the brewery Arthur Guinness took over in 1759. The self-guided tour works its way through seven floors covering ingredients, the brewing process, advertising history (those famous Gilroy posters), and the global spread of the brand.
The destination is the top-floor Gravity Bar, a glass drum with 360-degree views over Dublin's rooftops, where your ticket includes a complimentary pint. On a clear day you can pick out the Wicklow Mountains to the south. The Guinness is exceptionally well-kept, for obvious reasons.
Book tickets online to avoid the queues, especially in summer. Allow two hours for the full experience.