Final answer:
To see Tower Bridge, St Paul's Cathedral, Big Ben, and Westminster Abbey, you would need to visit London.
Step-by-step explanation:
If you want to see Tower Bridge, St Paul's Cathedral, Big Ben, and Westminster Abbey, you would need to visit London. London is the capital city of the United Kingdom and is known for its famous landmarks and historical sites. Tower Bridge is an iconic symbol of London, while St Paul's Cathedral, Big Ben, and Westminster Abbey are significant cultural and architectural landmarks.