Madrid in $510s-$540s RT

Houston, we have a deal. 

If you're looking for the cheapest entry point into Europe this summer, these fares to Madrid are the lowest we've spotted (so far). 

Spain's capital is sizzling in summer but nothing you can't handle, promise. Plus, with top-notch train services stretching across all corners of the country, you're never too far from its quaint seaside villages or grand seaside towns of the much cooler north. 

Just make sure to book accommodation in advance especially in places like San Sebastian - everybody and their brother escapes to the north this time of year.

And if you can't swing it, there's always Andorra...