Reykjavik, Iceland. Shutterstock The most successful economies in the world have large-scale and efficient infrastructure.

This requires continual investment from businesses and the government in order to remain competitive and to keep an economy running smoothly.

The World Economic Forum's Global Competitiveness Survey looks at the financial health and risks of countries around the world.

One of the sub-indexes ranks countries' infrastructure after scoring them from 1-7. A score of 7 is the best you can get.

While no country scored a perfect 7, there are a number of countries that claimed a score of over 6.

So we decided to take a look at the top 21 countries for infrastructure, out of WEF's assessment of 138 countries in total: