Since it announced at its Partner Summit in June it was coming, the first Snap activation of its kind goes live today and it centers on Carnaby Street in London as the new 'City Painter' collaborative AR project of Snap.
Local Lenses essentially allow users to interact with an AR overlay of a real-world location. You can virtually paint whatever you like over the shops and streets, and your contribution will then be visible to any other Snapchat user who visits the site.

The process is essentially an expansion of Snapchat’s ‘Landmarkers’ AR option, which enable users to apply Lenses that interact with global landmarks, like The Eiffel Tower, Buckingham Palace, or the Flat Iron Building in New York.
Local Lenses apply the same approach, but on a broader scale, mapping entire streets in the AR, and creating a persistent, evolving digital re-creation of the space.

This, in turn, might lead to entirely new, interactive AR experiences like looking at a restaurant and getting an overlay with a menu, or checking session times for a cinema. But currently, Snap is only in the early stages of full AR space mapping, and interactive digital art spaces are the next step forward.

But of course, for the moment, Snap claims to have "taken that idea, and run" with it. Facebook had experimented in something similar with its SLAM virtual art installation project back in 2017, but Snapchat also tried its own version of virtual displays which place an artwork in space which people may visit, but this time Snap includes an interactive aspect to bring out their digital installation toolkit to greater levels, which could point, as noted to the next stage for the implementation of AR.

Which, of course, would also be connected to AR glasses, which Snapchat might or might not be working on. But Facebook is indeed, along with Apple. Indeed, it's possible that instead of evolving its Spectacles product on its own, Snapchat could be looking to team up with Apple on its AR glasses, given how Snap has worked with Apple in the past on several AR tools.

What both may need to do in order to challenge Facebook is move fast on a combined Apple/Snapchat AR wearables approach, because the wearable AR clearly is the next stage and it's not 100% clear yet how Snap plans to keep up with that shift when it does eventually come.

Local Lenses are, indeed, a step in that direction, but exactly how Snap intends to evolve its Spectacles into a fully-functioning AR tool, we're yet to know.
Any which way, this is another interesting development, pointing to the next stage for digital engagement with real-world spaces. And that, eventually, will also facilitate new advertising and outreach opportunities via the same.