Cave Tubing, Zip Line and AltunHa Tours in Belize. Challenge Travel and Tours is the leading attraction at the park offering cave-tubing and zip-line tours. We also offer tours to the Maya Ruins of AltunHa, Lamanai and Xunantunich. CTT is here to satisfy your every need while in Belize. We are safe, reliable and fun!!We now offer nature tours to; the Belize Zoo and our very own "Monkey Business".