"The word 'tariffs' is the most beautiful word in the dictionary." So says Donald Trump – and with a new US administration now in office, an age of dramatically higher trade tariffs may be about to dawn. However, he's far from the first American president to dabble in tariffs.

By some estimates, higher tariffs could raise hundreds of billions a year for the US, but Trump isn’t only after an income stream. He wants to tackle alleged drug and immigration failures by his trading partners, and he also believes he can improve the American economy by reducing its reliance on imports. According to critics, he’s making a disastrous mistake. 

So, what’s the truth? Can tariffs and trade protection work? And what happens when they don’t? Read on to discover the impact of tariffs from ancient times to the present day and find out why they've always been controversial. 

All dollar amounts in US dollars.