Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

How to change a large quantity of U.S. dollars into Euros?
Be careful of transferring through the large banks. They may say no/low fees, but they hide their cut in the spread, or worsen the exchange rate, to their favor. Try:  - http://fxglobaltransfer.oanda.com/