Forgive slightly long and rambling post. At first, as I was trying the search, I thought you had to describe the kind of event, so I couldn't make it happen. The search is for the actual word "event" or "events" plus the <cityname>. It doesn't seem to work with any other location type, nor with any keyword more specific than "event(s)". Google describes the results in the serps as...
Placename / Events ...noticeably hierarchical.
The closest I'd seen to this previously was posted back in March by aakk9999, who also posted a screen-capture, so we've got that to compare...
Another SERPs Knowledge Layout - No Organic Above Fold March, 2015 https://www.webmasterworld.com/google/4742084.htm [webmasterworld.com]
It's triggered by searches in the form of...
camping placename All of these are arranged in a grid layout in columns of 3 or 4 entries, etc, as appropriate. Destinations had thumbnails for each placename listing. Events only have a thumbnail for the "city". This is the same as the image used in the Knowledge Graph listing for the city that shows up simultaneously in the usual spot on the right, though now below the rows of events. Sidescroll arrows for both types of searches then serve to shift the rows of the grid right or (eventually) left.
Some evolution from the screen capture. Back in March, Google showed them in the serps as
Placename > Destinations, but now a more hierarchical "/" is used. I should note, btw, that for the Destinations results in the US, "placename" can be either "United States" or a Statename. If I change to the city level, I get some places results with a map, as if camping in cities is more likely to be commercial than camping in states, and Google seems to be separating some commercial entities from non-commercial.
When other searches go commercial at the city level (eg, "hotels"), right now I'm getting either the old image carousel, which I haven't noticed for a while, or a 3-pack and maps results (testing again?), depending on the size of the city... and with cityname hotels too there's no indication of the (Knowledge Graph) hierarchy that we're seeing both with Destinations and with Events.
There's something else I've noticed, though, which adds a startling aspect to this... up in the top left of the page, above the Placename in both Destinations or Events, the word "Web", which I've long remembered had that default spot in the organic SERPs, has become
"All".
Among other things, this is probably suggesting that Google is going beyond the web for its information in these searches, as it has for a while, but is now stating that clearly.
See new thread I've just started on this... and in fact interrupted posting of this one to post it....
Google changes "Web" to "All" in verticals on SERPs https://www.webmasterworld.com/google/4782540.htm [webmasterworld.com]