Slightly spooky treasure hunt (week 1)

This is not a typical meetup where people show up at the same place at the same time.

At the starting time of the meetup (Oct 2nd, 12:00) the first hint will appear somewhere here on this event page. If it doesn't, then it didn't, but it will. This hint will start a treasure hunt. The treasure hunt can be completed for one whole week. You can do it whenever you want during that time. Feel free to use the chat or the comments to find people to group up with (highly suggested).

The treasure you'll receive might be helpful for the spooky finale (👀 28.10.)
There are 3 treasure hunts before the finale.
They can all be completed independently, so don't worry if you miss one.
They are not needed for the finale but they might make you more happy.

🐇.. 🐇.🐇 . . .🐇. 🐇... 🐇 . 🐇🐇.
Important:
If you find anything, please please please leave things the way you found them (unless told otherwise), so others after you can also have fun.

This is an experiment and there are things hidden in public places. Because of this I cannot guarantee, that random people won't remove stuff (although I tried to make it hard for stuff to be found on accident). If you are sure you're in the right spot, but can't find anything, please send me a message and I'll try to fix it asap.

Also:
You've received a letter 👀
🐇.🐇 ..🐇 . .🐇. 🐇.. . 🐇 . 🐇..... 🐇