The challenge here is both simple and not easy all at the same time (that is, if you live anywhere near this cache). It's simple because you only need to find 1 cache to complete it. And according to project-gc there are currently almost 6,000 active caches in just the US alone that would qualify you for this challenge. The hard part is that the nearest of those qualifying/active hides is nearly 1,000 miles away. In order to log this cache, you must have found at least one cache (of any kind EXCEPT for locationless caches) hidden at an elevation of 0ft or lower. You can verify if you qualify a the checker below.
Congrats to Hal-oween on a very speedy FTF!