Canada's Cold War Museum ('The Diefenbunker'), Rideau Hall & The Glebe (Lansdowne)

Once you have explored Parliament Hill and the riverfront museums, three distinctive Ottawa sites show you a completely different side of the capital, from a four-storey subterranean nuclear fallout bunker to the ceremonial woodlands of the Governor General's residence.

1. The Diefenbunker: Canada's Cold War Museum (3929 Carp Rd, 30 Minutes West of Downtown)

At the height of Cold War nuclear tensions in 1959, Prime Minister John Diefenbaker ordered the top-secret construction of a four-storey, 100,000-square-foot, 300-room underground bunker buried inside a gravel hill in the rural village of Carp just west of Ottawa (dubbed 'The Diefenbunker' when investigative reporters discovered it by counting 78 toilets being delivered to an empty farm field). Designed to seal 535 top government leaders and military commanders underground for 30 days after a nuclear strike, it was decommissioned in 1994 and is now a National Historic Site of Canada:

• What You Walk Through Inside: enter through the 115-metre-long curved corrugated-steel Blast Tunnel and decontamination showers to explore the Prime Minister's underground suite, the Emergency War Cabinet Room, the CBC Emergency Broadcast Radio Studio, and the colossal Bank of Canada Underground Gold Vault (built with a 34-tonne steel door to store Canada's gold reserves during a crisis).

2. Rideau Hall (1 Sussex Drive, Free Grounds & Free Guided Tours of the Residence)

Ten minutes north-east of ByWard Market (via Bus 9 or a walk past the 24-metre twin curtains of Rideau Falls where the Rideau River plunges into the Ottawa River), Rideau Hall has served since 1867 as the official residence and workplace of the Governor General of Canada. Its 88-acre (36-hectare) wooded estate is free to walk daily (where visiting world leaders from John F. Kennedy to Nelson Mandela and Princess Diana have planted ceremonial trees), and you can take a free 45-minute guided tour inside the 1838 Tent Room and Ballroom, plus watch summer Ceremonial Guard shifts and skate on a free outdoor 1872 winter rink.

3. The Glebe & Lansdowne Park (10 Minutes South Along the Canal on Bus 6 or 7)

Follow Bank Street south across the Rideau Canal into The Glebe, Ottawa's Victorian shopping neighbourhood, anchored by the restored 1905 Aberdeen Pavilion ('The Cattle Castle') at Lansdowne Park, which hosts the Sunday Ottawa Farmers' Market year-round.