St. John Cantius Roman Catholic Church in Chicago has a huge collection of relics of various saints. There's nothing magical about them but they are a way to help establish a connection to members of the body of Christ that have preceded us to Heaven. Praying to saints is the same as asking our friends to pray for us. Catholics know that saints can't do anything for us other than to pray to God for us, just like our friends on Earth. Just as God encourages us to pray together, see Matthew 18:19, He also encourages us to pray to the saints. Saints are just people who've made it to Heaven. The folks who are declared saints by the Church are those have had miracles done for them by God after they've died. Presumably God does this to provide us with role models, real people who've made it to Heaven. There example helps us better conform our life to Christs, just as they did.