The most common and most likely answer to this crossword clue is the 7 letter word SIBERIA
I've seen this crossword clue in The Guardian
S
I
B
E
R
I
A
More clues leading to the result SIBERIA
- Remote region of southern Spain and Portugal
- Lives overturned by Soviet police chief in gulag setting
- Southern peninsula in part of modern Russia
- Brother or sister, on time, collecting one in Asian region
- Bear is swimming around island in a chilly part of the world
- Greek character more intoxicÂated, we hear, in region of the far north
- Southern peninsula, a massive area
- River again rising in extensive Asian region
- Part of Russia is revolting and reportedly less than sober
- Italy in Serbia, foreign country
Buddy explains!

The straight part
We know that "a massive area" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a massive area = siberia.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.