Without a doubt, the highlight of the Grand Avenue Tour was Frozen Niagara, with gorgeous flowstone, stalactites, stalagmites, soda straws, and draperies. If you sign up for the 4-hour, 4-mile Grand Avenue Tour, the good news is there are actually flush toilets on the route (amazing!), so no worries on that score. The groups are big (we had 78 people), but they manage it well, and Ranger Chris had a big voice, so we could hear his descriptions and historical accounts just fine.