The word 行(い)きます ikimasu means “to go”. We change it to the tai-form ～たい to mean “want to go”. Similarly, you can use the tai-form for any verbs to mean you want to do something. For example, 食べます tabemasu (to eat), 食べたい tabetai (want to eat); 飲みます nomimasu (to drink), 飲みたい nomitai (want to drink).
I hope that you will get a chance to visit Japan someday.