Purgatory and the Souls of the Faithful Departed
The Catholic Church teaches the existence of Purgatory as a Doctrine of Faith
"Those who die in God's grace and friendship imperfectly purified, although they are assured of their eternal salvation, undergo a purification after death, so as to achieve the holiness necessary to enter the joy of God."
Catechism of the Catholic Church, No. 1054
Also in Spanish.