8. Alexander Nevsky Cathedral

Alexander Nevsky Cathedral at Toompea

This beautiful church atop Toompea hill cannot be missed. It’s the main Russian Orthodox church in Estonia and is considered an architectural masterpiece. The church doesn’t only feature a gorgeous and colourful interior, but it also has the largest number of church bells in Tallinn – a total of eleven, including the largest bell in the city which weighs 15 tonnes.