A very large pot that ends in "at" is called a "cauldron." Cauldrons are typically large, deep vessels used for cooking or boiling liquids, often associated with folklore and witchcraft. They have been used historically for preparing food, brewing, and even in rituals.
Mushroom.
A magnum is a large bottle, carboy's are another.
Sequoia
another word for very large
A mansion.
Methusela
A synonym for a very large area within a continent is a region.
very close
This answer is not very descriptive so I can not answer this question
behemoth
Another name that is very, very similar to the color of purple is violet.
Another name for a palace is a Mansion. A palace or Mansion is a very big house.