I try to give a list, but this may not be exhaustive:

-) pyramid
-) valley of kings
-) this tomb in Spain
-) babylon quest
-) praying to a god you worship (not christian)
-) praying to Christus if you worship him
-) if you are part of Rome do the quests for Nero, they will lead you to find the tomb of Arminius
-) winning Olympics gives you a laurel
-) becoming pharaoh of Egypt gives you crown of Egypt (only possible as Emperor event)