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

● Middle-earth ,

● Arda (Tolkien's Universe).

The tallest mountain on Middle-earth might not be the tallest in the entire Legendarium, which is why I have extended the question to include Arda as a whole. For example we have Menelterma which is the highest mountain on Númenor. Is this taller than Middle-earth's highest mountain?

What's the tallest mountain in Middle-earth and Arda?