Palindromes and dates go together. This is a palindromic time in the US, where we have 12 for December and the end of the year 2021 being 21. But in much of the rest of the world, they don't write the month first - 2 December 2021 or 2 12 2021 - is not palindromic. But for those of us in the US, December 1st through 9th this year can be written palindromicly. December fifth is in the middle of that sequence: 12 5 21.
The festive container is hanging by the creek. It is not in an unsafe place, but shorter people may have to stretch. It's not very hidden.
Congratulations to NoBlueCircles on the quick first-to-find.