When you go to air travel reservation sites, be they run by the airlines or the aggregators, you need to enter specific travel dates in order to explore the possible ways to get from here to there. Is there a way to do more general exploration? Starting from our local airports, is it possible to get to destination X nonstop, via 1 connection, etc.? Where would the connections have to be made? When we are at the "where do we go next?" stage of planning, we'd like to know how hard it is to get there, before descending into the detail of specific flights.
Google flights is one of the best search engines.
Baltimore airport and Dulles both have entries in Wikipedia listing all the direct flights international from those airports
Hmmm, well seeing you are from the DC area I'd go to the Dulles Airport website and see what non-stop flights are offered from there which may or may not be on your airlines of choice.
For someone like myself who is flying from an end-of-the-line 1-gate airport, lol, I go to my hub (SLC or SEA) and check out the non-stops each airport offers, then drill down to airline. I'm partial to Delta so pretty much know I'll go to a European hub like AMS and change from there.
Have fun deciding where to go next!
I use a website called FlightsFrom to look at nonstop and connecting flight options from various cities.
Delta has that...not sure how useful it is for you in DC though as that's not a Delta hub.
Rome2rio is a great website for researching itineraries. Train and bus services are also quoted. I’ve found it very accurate, and it’s one of my favorite resources. https://www.rome2rio.com/
I have never tried to use Rome2Rio for air connections, but I've found it potentially disastrously inaccurate for ground-transportation fares, travel times and frequencies. It seems better at telling you where you'll need to transfer, so that could be helpful in certain circumstances for air itineraries. However, it doesn't give you the quick-look-at-fares-on-map option that's available (for round-trips) on Google Flights.
I use google flights. In "from" put your home airport, in "to" put "Europe" and then a date, look at one way flights (or round trips, or multi city open jaw), and I like to look for one stop trips if not non-stop depending on where you start from...also helpful to look at, say, Istanbul to Europe if as I am trying to figure out the end of a planned trip later this year and I want to get to the western edge of Europe for a few days before flying home, hopefully on a non stop. Once you get the hang of google flights it becomes indispensable in planning, seeing what is feasible, and keeping track of prices.
At www.skyscanner.com, I don't know that you can enter a whole continent as a destination, but you can enter a whole country and a whole one-month period, before filtering for fewer connections drilling down on the cheaper price results.
Thanks to everyone for those suggestions.