Niagara Falls exists because of the last Ice Age and the peculiar geology beneath the Great Lakes region. When glaciers retreated roughly 12,500 years ago, they left behind a landscape of interconnected lakes. Water from Lake Erie began draining through the Niagara River to Lake Ontario, but a cap of hard dolomite rock resisted erosion while softer layers below eroded away. The result was a waterfall that has been eating its way upstream ever since, retreating at an average rate of about three feet per year. The falls began at the Niagara Escarpment near present-day Queenston-Lewiston, seven miles downstream from their current position. At current rates, they would reach Lake Erie in approximately 50,000 years - though human water diversion has slowed the retreat considerably.

The international boundary runs through the middle of Horseshoe Falls, but geography favors Canada. The Canadian side offers direct, head-on views of both the Horseshoe and American Falls, while the American side provides close-up encounters but less panoramic perspective. The Canadian city has embraced tourism completely: Clifton Hill's neon attractions, the Skylon Tower, casinos, wax museums, and haunted houses create an atmosphere some find charming and others find excessive. The American side offers more parkland and a more subdued atmosphere, including the historic state park that predates most other American parks. Both sides offer the essential experience: Maid of the Mist boat tours (now called Hornblower on the Canadian side) that approach the base of Horseshoe Falls, soaking passengers in spray as millions of gallons per second thunder overhead.

Niagara has attracted thrill-seekers since Annie Edson Taylor became the first person to survive going over Horseshoe Falls in a barrel in 1901. She was 63 years old. Others followed: some survived, many didn't. Tightrope walkers crossed the gorge starting with Jean-François Gravelet (Blondin) in 1859, who repeated the feat while blindfolded, pushing a wheelbarrow, and carrying his manager on his back. In 1960, a seven-year-old boy survived an accidental plunge over Horseshoe Falls wearing only a life jacket. All stunts are now illegal, prosecuted vigorously by both countries, yet people continue to attempt them. The falls have also frozen spectacularly - in 1848, ice blocked the river upstream, reducing the falls to a trickle; in extreme winters, ice bridges form below the falls, though these are now off-limits after a collapse killed three people in 1912.

The same force that draws tourists also generates electricity. Hydroelectric development began in 1881 and expanded dramatically through the twentieth century. Today, diversions send roughly half the river's flow through tunnels to power stations downstream, with international treaties governing water allocation. The falls themselves are literally turned down at night and in winter when tourist crowds thin - flow is reduced to increase power generation. A 1969 engineering project temporarily dammed the American Falls entirely to study erosion, revealing a massive talus slope of fallen rock at the base. Proposals to remove the talus were rejected; instead, both nations committed to maintaining the falls' natural appearance while continuing to harvest their power. Queen Victoria Park on the Canadian side and the New York State Reservation on the American side protect the immediate surroundings.

Niagara functions as a day trip from Toronto (75 miles) or Buffalo (17 miles), though overnight stays allow experiencing the falls illuminated at night, when colored lights play across the cascades. The Canadian side offers more commercial infrastructure; the American side offers a more authentic park experience. Crossing the border is straightforward on the Rainbow Bridge or Whirlpool Bridge, though wait times vary. The Maid of the Mist / Hornblower boat tours operate from both sides and remain the signature experience - cheap ponchos barely protect against the wall of spray at the base of Horseshoe Falls. Journey Behind the Falls (Canadian) and Cave of the Winds (American) offer tunnel-accessed viewing platforms. Beyond the falls, the Niagara River's whitewater, the Shaw Festival at Niagara-on-the-Lake, and the Niagara Peninsula wineries extend the region's appeal far beyond the single spectacular attraction.