Took my grandmother from South America here. She loved it. We went there on a rainy day and I guess everyone went that day. We had to wait outside in the rain in a LONG line. Fortunately, it only took a little longer than 30min to get in. And they were wise enough to string along a long line of standing rain coverage all along the sidewalk so we were not standing in the rain. Major kudos for that. Once inside the tour can take a long time, about an hour plus. But its a lot to see, listen to from the tour guide and take pics of. It is surely a place you MUST see in your life simply because most places don't have stalagmites or underground caves. Just be prepared for a lot of standing and a good amount of walking as well (a little over a mile). Its best to eat before you get here or after. The food places here are VERY expensive.