The Island of Destiny

You continue trekking onwards to the mountains. As the ground begins to get rockier and hillier, you find yourself having to stop to catch a breath. The next thing you know, you're looking down and finding yourself pretty high up. The jungle hangs way below you, seeming much less threatening now that it is so small at the altitude. You can also now finally see how big this island really is. You would guess that the island is a couple dozen miles in diameter, with jungles and mountains lying in all directions.

You do see that at the top of one mountain in the distance lies a tower. It is a dark tower with a pointed prong at the top of it. It strikes your curiosity in a way you haven't felt for a very long time. You want to go there.

You walk along the rocky hills of the mountain and step down into a canyon. You see a running stream of water and go over to take a drink. You scoop down for the water and man, it tastes like the best thing ever. There is some healthy vegetation in the grove around you and you notice a hole going into the mountain. Peering over, you see that the hole is perfectly circular. It's small and to get in, you wouldn't be able to do much more than army crawl.

Should you venture inside this hole? Or should you forget about it and continue on towards the tower?