400. That’s an error.

Google cannot redirect you to http://www.amazon.com/exec/obidos/external-search/?field-keywords=Crist%C3%B3bal+Col%C3%B3n,+hombre,+genio,+m%C3%ADstico&index=books because the request was invalid.

This might be because the link was created a long time ago. Try your search again on Google. That’s all we know.