Ideally, the ‘festivals’ page would contain a list of hyperlink enabled images with alt-text for each venue.
When you click on each named festival, they would open their respective page in a new tab.
Each page would open in a collapsible text format, sorted by year. In otherwords, you could expand 2017, whilst leaving the 2016 section collapsed.
The individual festival year post could contain a ‘click on load’ slideshow, along with a review, or multiple reviews.