Fill in: a/an or the where necessary

1. [a|an|the|] Big Ben in London is not [a|an|the] building; it's [a|an|the] enormous bell in [a|an|the] clock tower?
2. [a|an|the] blue whale's call is the loudest noise made by [a|an|the] animal?
3. [a|an|the|] Kangaroos can hop along at speeds of up to 56 kilometres an hour?
4. [a|an|the|] Alaska is the largest state in [a|an|the] USA?
5. [a|an|the] Amazon River crosses three countries in [a|an|the|] South America?
6. [a|an|the] Chinese invented ice cream in 2,600 BC?
7. [a|an|the|] Mount Everest grows 4 millimetres [a|an|the] year?
8. [a|an|the] Taj Mahal in [a|an|the|] India is [a|an|the] World Heritage Site?
9. [a|an|the|] Vatican City in [a|an|the|] Italy is actually [a|an|the] country with its own government?
10. [a|an|the] Spanish Steps are [a|an|the] popular meeting place in [a|an|the|] Rome.