The Holy Eucharist is the "source and summit of the Christian life" (LG 11, CCC 1324). We, Catholics believe in the Real Presence. The Eucharist is not a symbol or a reminder. The Eucharist is Christ truly present, his Body under the form of bread, the Blessed Sacrament, and his Blood under the form of wine, the Precious Blood. It is the "Heart of the Heart of God" (Fr. Simon referencing to approved Eucharistic miracles scientifically proven to be heart tissues). It is the sacrament in which Jesus is truly present - Body and Blood, Soul and Divinity under the appearances of bread and wine.
   
The Feast of Corpus Christi is one time when our Lord in the Blessed Sacrament is exposed not just to faithful Catholics but to all the world. This is a time when Catholics can show their love for Christ in the Real Presence by honoring Him in a very public way. It is also a wonderful way in which we can show our love for our neighbors by bringing Our Lord and Savior closer to them. So many conversions are a result of Eucharistic Adoration experienced from inside the Church. How many more there would be if we could reach those who only drive by the church in worldly pursuits.  (therealpresence.org)