Museo Maritimo Del Cantabrico is a perfect place to get a glimpse of fascinating marine life. It is also known as Maritime Museum of the Bay of Biscay or MMC. It focuses on the rich marine biodiversity, most of which is still a hidden gem and how humankind and sea are connected. Many of its collections started taking shape in the 18th century and are divided into 4 expansive sections. If you are looking for things to do in Santander with kids, taking a tour here should be on top of your list.