Jesus said that he would prepare a place for his followers, and He has prepared the way for the saints (believer's) for their Eternal Life and when everything is ready He will come.
No one knows when that time will be but all are to be expectant.
To the world Christ's Return will be totally unexpected. Christians, are to be prepared for they do not live in the dark they have the light of The Word of God which guide believers to notice what is going on in the world, for there are signs given, that mark His return.
When Jesus Himself spoke of His Second coming, He illustrated to all that it would be a spectacular affair and that everyone will know that He will have arrived.