Lego train with some puzzle (part 2) [lvl1]

This second train will be a bit different from the previous one, with puzzles themed around geocaching.
Finding the caches will be possible using the given coordinates and the description of the hiding spot. However, you may often need additional clues, such as reviews and photos posted by previous finders.
If you hit a wall while solving a puzzle, I'll be keeping an eye on feedback and can offer a hint or two to help. Have fun, everyone!
(Feel free to skip the italicized flavour text sections.)

General Tips:

• Most of the puzzles involve Google Maps.
• The provided/solved coordinates are accurate; if you don't find anything within a 10-meter radius to click on, try zooming in and out. If nothing shows up, you're probably in the wrong spot.
• Although I call it geocaching, in this game, you don’t need to find the caches—focus on the codes."

The train journey is comfortable, but you soon start to get bored. At the next longer stop, you decide there's just enough time for a quick geocaching adventure. Searching nearby on the web, you find the closest cache:

CACHE 1
Location: 39.447204, -6.405313
Description: I’ve hidden the cache near a big rock with a cross shaped stone carving. The code to open it is in a visible spot. Good luck with the find!

HINT:
if you find something but don't know what to do with check out zelgh's guide to get an idea
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there's a tool in the guide above, use a method where "WW91IHNvbHZlZCBpdCE=" makes sense