As far back as the 1820's, the region of the Canadian Shield where the town of Marmora sits was known for being rich in iron. Mining operations were established to extract the precious metal from the earth, particularly along the Crowe River, where the remains of many operations still stand.

One particular mine, the Marmoraton, was known as the most successful and established itself in 1953. Owned by Bethlehem Steel of New York, the mine required the blasting of limestone to depths of 120 feet to reach the ore; at the time of closure, a whopping 1,224,000,000 cubic feet of material, weighing 1.3 million tons, had been removed and the mine was reaching depths of 600 feet.

In it's heyday, 300 men were employed and filled upwards of 35 rail cars full of the ore, which was sent back to New York for processing. Now it sits, with the effects of water infiltration having filled most of the mine pit with water, leaving a large man-made lake. Along the pit are the remains of structures, including several buildings still standing just east of the crater.

However, these buildings sit on a part of the mine that is still active (I'm not sure what they are doing with it, but there are people working there)... and this is where the problem exists. Security is not afraid to come after you (as we discovered when we were chased off the property). But if you're feeling adventurous...

As far as hazards go... play it smart and be careful around the pit edge. It's a long (and likely fatal) drop to the water below.