What is the difference between verbs "ser" and "estar"?

Because both verbs can be translated to "to be<" in English, distinguishing them can be particularly difficult for students. The verb "ser" is used to describe permanent/unchangeable states or qualities of the object - e.g. "ella es alta" (she is tall), or "España es un país" (Spain is a country). On the other hand, the verb "estar" serves to describe the state of the object only in a given moment - e.g. "yo estoy cansado" (I am tired). Furthermore, "estar" can also be used to indicate the physical position of the object - e.g. "Juan está en su casa" (Juan is in his house).