Niagara Falls is the reason ships can't simply sail from Lake Ontario to Lake Erie. The Welland Canal is how they get around it, and in Thorold they do it in one of the most remarkable ways in the world.
A staircase for ships
The Welland Canal runs 43.5 kilometres from Lake Ontario to Lake Erie, lifting ships about 100 metres in total through eight locks: seven lift locks, plus a guard lock at Port Colborne.
In Thorold, Locks 4, 5 and 6 are built as twin flight locks. Instead of separate locks with stretches of canal between them, they sit end to end, like a staircase, so a ship steps straight from one into the next. Together they stretch about 1,250 metres and raise ships about 42.5 metres up the Niagara Escarpment. Because they're twinned, one ship can climb while another descends beside it.
Nearly two centuries of canals
The first Welland Canal opened in 1829, championed by St. Catharines businessman William Hamilton Merritt. Larger canals replaced it over the following century, and today's Welland Canal, the fourth, opened in 1932. A 13.4-kilometre bypass around Welland was added in 1973.
The Welland Canal system was recognized as a National Historic Event in 1924, and its plaque is at the Lock 7 Viewing Centre, 50 Chapel Street South in Thorold.
See it for yourself
Watching a ship the size of an apartment building rise past you is something every Niagara resident should do at least once. The Lock 7 Viewing Centre is a good place to start, and the Twin Flight Locks are a short drive away.