"The boating experience here is unlike any other. A vast maze of waterways is composed of slow-moving rivers, marshes and mangrove forests," said Boatmart in a blog post.
'We all know, and lazily accept, that going out for a night or down the country for a week is a more efficient way of getting mugged than wandering down a dark lane at midnight.'
Visiting Crystal Cave requires physical exertion and may not be suitable for everyone. Those with claustrophobia or other physical limitations should avoid the tour.