Hamilton's most distinctive natural feature is the Niagara Escarpment, which runs through the city and has produced over 100 waterfalls and cascades within the city limits — earning it the nickname "The City of Waterfalls." Dundurn Castle is the most impressive historic site. The Canadian Warplane Heritage Museum and HMCS Haida are both strong options for history-focused visitors. The Royal Botanical Gardens straddles the Hamilton-Burlington border and holds the world's largest collection of lilacs.