I apologise for not being able to provide screenshots or anything of the like as the site is down of writing this but I did write this up quickly to give people an idea of my process

1. My first thought was to google line and dot numbers which turned out to be the mayan counting system.
2. Knowing the culture, I google “Kulkulkan” and “Mayan” which led to the location Chichen Itza. I also noted that Kulkulkan’s stronghold was constructed sometime around the 8th to 12th century (will be important later)
3. Now that I have the location, I googled for past solar eclipses and found a NASA website which required the latitudinal and longitudinal coordinates of Chichen Itza.
4. After doing another quick google search, the coordinates were found and inserted into the NASA page.
5. After reaching the 11th century, it was noted that there was a total solar eclipse on 11/07/1097.
6. Confirmation from submission proved the flag to be:
nicc{1097-07-11_Chichen_Itza}