Quick disclaimer: I played through this journey on peaceful mode so I wouldn't have to waste time hunkering down in a shelter at night to avoid hostile mobs. Also, I'll link Niall's own story of Minecraft as it is of similar style, being a travelogue.
Having explored the deepest depths of Minecraft, both by mining and by spelunking, I didn't think anything could surprise me anymore. Sure I'd stumble across a floating island every now and again but nothing too extravagant.
I found a compendium of useful Minecraft tools on the official forums the other day and found Cartographer to be an especially useful tool. Cartographer is a small .exe program which scans your save file and maps out the area in its entirety.
Click for a larger version. You know you want to!
After scanning it for a bit, I managed to find my home as well as other landmarks. Campsite Beta right outside Devil's Maw Falls, Gravel Pit, the Icy Igloo Cabin. But one thing caught my eye especially: a huge group of red tiles to the south of my home. From the size and color of the mass, I deduced that it was a mountain covered in lava five times larger then my home's property lines.
I had to see this mountain for myself. Lava normally only appears deep underground. But this could be a volcano in the middle of this ice age of a world. A world so cold that almost all surface water freezes solid. I packed my essentials and made my way through the whited out land towards Death Mountain.
I started heading due south and hit this alcove. Dubbing it Spring Cave Garden, I made a home near the natural spring to later explore the caves for a dungeon indicated on my map.
Heading further south I found something I forgot I had left behind in an earlier excursion. A series of torches, dotting the rugged landscape with warmth and light, piercing the darkness and making clearings of grass: the Trail of Light.
I could recognize the trail from the map due to the yellow dots surrounded by grass as the light melts nearby snow. It's impossible to get lost now that compasses have been added into the game, which always points towards your original spawn point, but seeing the lights was a big comfort in the dark wilderness, where no city lights exist.
It's inevitable to pass by a number of caves. Exploring each I come across would be time consuming, but something called out to me about this one.
It held another underground spring, always a nice geographical feature to discover. The sound of running water is a big treat as I normally play with no music playing.
I also found another cave, except it didn't go hundred of feet underground. It was naturally formed, making it the perfect home to furnish should I come back. Very little work is necessary to get it off the ground. It even already had a window space ready for me! Yogi bear would be proud to live here.
I finally hit the end of the Trail of Lights. I left behind a large arrow made of dirt to commemorate the end. According to the map, a smaller mountain of lava should just be a bit due west from here.