I've felt that both of these examples are correct:
Die Welt zu sehen
Die Welt sehen
I've seen the zu be used and omitted in various sentences.
My suspicions are that these have a slight different meaning of:
To see the world
Seeing the world
I would like someone to confirm of this is correct.
Also, if they are both correct, can they both be used in a normal sentence e.g.
Die Welt zu sehen ist wichtig für mich
Die Welt sehen ist wichtig für mich