How do I use a variable so that it is inside and outside of a function

I would like to know how I can use a variable in a function but then outside of the function as well. Here is a part of my code which is supposed to add 1 to the score when the answer is correct, then print out the overall score afterwards (there is more than one function so I need to the score to be outside of the function):

score=0
def Geography(score):
#Question 1
qa1= input("What is the capital of England? ")
if qa1.lower() == ("london"):
    print ("Correct you gain 1 point")
    score=score+1
else:
    print ("Incorrect")

Geography(score)
print ("This quiz has ended. Your score is " , score, ".")

As you can see, I have tried to use arguments however the code still returns the score as 0 at the end no matter if the person has got the answer right.