What you need to know about Bilbao… Tours By Basques. Thats it. Let Mikel take your hand and show you around his city. No amount of research can replace meeting a local guide and spending half a day with him. Without a tour, we could be passing by a Pintxos bar, seeing napkins all over the floor, going “Feh! this is disgusting. Lets find another one”. When in fact it is not only perfectly alright but advisable to throw your napkins on the floor. So a mountain of dirty napkins on the floor is actually a sign of a good local bar.
What you need to know about Gaztelugatxe… Just go! Its one of the more exciting reasons to visit North Spain. Give it about 3 hours, and try to arrive as early as possible on a weekday preferred. It got a lot more popular lately after Game of Thrones (Gaztelugatxe is Dragonstone).
What you need to know about Guernica… A couple of hours in this sleepy town will not be enough to fully understand its importance. But its a good place to pair with Gaztelugatxe. Have lunch at Boliña (There are two different Bolinas close to each other and both are good), see the “Guernica” mural, and of course Casa de Juntas