The MilkyWay bar sold in the US is different than what you'll find in any other country.
In the states, the MilkyWay Bar features nougat topped with caramel, covered in milk chocolate. The rest of the world knows this combination as the Mars Bar.
The MilkyWay bar found in the UK (and the rest of the world) does not contain caramel and is most similar to the "3 Musketeers Bar". The international MilkyWay has a much lighter center nougat than the 3 Musketeers Bar.
The UK version of the MilkyWay bar is vegetarian friendly.