A quick urban cache.
You are looking for a small cylinder, smaller than a film canister. Fingers may be more useful than eyes.
You should be able to retrieve this between muggle traffic, but please take care.
Edit (September 2020): We have bumped the difficulty up from 1.5 to 2.5 based on the logs of those who found the cache. We (the owners) thought it wouldn't be hard to find, and indeed some do find it easily, but others have had to work harder. So 2.5 seems a more honest rating.