Our knowledge of the real world tells us that "however" is the right choice. You would expect that tourists would avoid a dangerous place. The fact that they like to visit them anyway is surprising. It is not what we expect from the first part of the sentence. Therefore we would use a word like "however." Instead of "however," we could use the words "but," "yet," or "nevertheless."
In a classroom, or on a test, the "right" answer is "however."
Just for fun, though, we can argue that "because" could POSSIBLY be correct. In order for it to be correct, we would need some explanation that says that TOURISTS make the desert dangerous! Consider this example.
"In the Sahara desert, the Egyptian Tortoise has become endangered from habitat loss and expansion of tourism. From the point of view of the tortoise, deserts can be very dangerous habitats because hundreds of tourists like to visit them."