KLM is having excellent deals on trips to Europe originating in USA. Many deals aren't even advertised. I just booked a RT from GRR (Grand Rapids, MI) to BRU (Brussels) in March/April for $485 after tax. Didn't see it advertised anywhere, but there are lots of great deals.
Go to Google Flights, type in your dates, select Skyteam as airline, and make sure you book through either KLM or AF for the sale prices. My same flight would have been $1500 if booked on Delta.