Complex sentence: Clock towers are a common sight in many parts of the world with some being iconic buildings like the one in London commonly called'Big Ben' (although it is correctly called the Elizabeth Tower as Big Ben is the bell inside the tower).
Split into simpler sentences: Clock towers are a common sight in many parts of the world with some being iconic buildings. One example is the Elizabeth Tower in London commonly called'Big Ben' (although this common name correctly refers to the bell inside the tower).