I looked this up just now and came up with this list:
Following are the religions that no longer exist.
1. SUMERIAN RELIGION
2. BABYLONIAN RELIGION
3. ASSYRIAN RELIGION
4. EGYPTIAN RELIGION
5. GREEK RELIGION
6. MITHRAISM AND ROMAN RELIGION
7. GERMANIC AND NORSE RELIGION
8. MAYA RELIGION
If this list is accurate, that really doesnt make me feel hopeful that the JW religion might someday be brought down. These religions are no doubt very, very old, and probably just small offshoots from some other mainstream belief system.