Bruce Peninsula National Park occupies only a small section of the peninsula itself, but there's other interesting spots outside the bounds of the park such as the lookout at Lion's Head, the Fathom Five National Marine Park at Tobermory and Greig's Caves. It's known for its rocky shoreline and crystal clear turquoise waters. Most of the popular hikes here are on the shorter side and low elevation gain, but there's some lengthier trails traversing the shoreline.
Even in the dead of winter, the color of the water shows through.
There's a few different ways to reach this spot, but I opted to take the Marr Lake trail to Boulder Beach and then loop back along the Georgian Bay Trail after checking out The Grotto. This resulted in a relatively flat and easy 2.4 mile hike along a frozen Marr Lake and the shoreline of the Georgian Bay at Boulder Beach, which definitely lives up to its namesake. This area and The Grotto can be very slippery in the snow, so exercise caution.
There's a few overlooks along this trail, but the final one is the best.
This hike takes about 2 hours to complete and has a little more elevation gain than The Grotto trail, but nothing too substantial. The trail mostly runs through flat forest with a brief stint towards the shoreline at the end, but views are obscured until reaching the lookout. There's a cool little cave along the trail called the "Lion's Head Pothole."