In Magento you can build a multilingual as well as a multi-currency website. In order to facilitate a multi-currency website, Magento asks you to setup [Admin >> System >> Configuration >> General >> Currency Setup] a ‘base currency’, a ‘default display currency’ and ‘allowed currencies’. The ‘base currency’ can be configured at global level or website level depending on your catalog settings at Admin >> System >> Configuration >> Catalog >> Catalog >> Price >> Catalog Price Scope while ‘default display currency’ and ‘allowed currencies’ can be configured at store view level.