There are many mountain in middle earth, From the harsh Misty Mountains to the humble Lonely Mountain. This made me wonder what's the tallest mountain in :

1. Middle Earth 

2. Arda  (Tolkien's Unviverse)

The tallest mountain on middle earth might not be the tallest in the entire Legendarium , which is why I have added  [2] . For example we have Menelterma which is the highest mountain on Numenor. Is this taller than Middle Earth's highest mountain  ?

What's the tallest mountain in Middle Earth and Arda  ?