This year, the San Mames Stadium is celebrating its 100th birthday, and already half built, the new stadium is going next door. That alone is worth the visit. We went on a Sunday morning and there was a huge line (moms with strollers, families, school groups, amazing). We bought our tickets and went during nap time, and there was still so many people. We first visited a mini-museum (no pictures allowed) leisurely, and then we started the tour. Apart from the stadium itself, there are a lot of worthwhile curiosities inside and things that the kids loved. A bust of Pichichi, a stuffed lion, the only Spanish stadium arch.