This series of challenge caches will trigger you to pay more attention to the specific attributes when you find a geocache.
To qualify for these challenges, you need to collect any attributes in such a way that they occupy all find days 1 to 31 of the monthly calendar.
For this particular challenge cache, 30 different Attributes are required.
The following levels for this type of challenge can be achieved:
20 Attributes - GCABXB5
30 Attributes - GCABYXK
15 No-Attributes - GCABXCC
Qualifying caches can be of any type, found date and location.
The checker below will tell you if you qualify.
You can find the exact same challenge in Berlin at GC9QV0N . Thanks to Tacimedes for allowing me to duplicate the series in Queensland.