FreeThe national memorial to the 1994 genocide against the Tutsi, set on a hillside at Gisozi where more than a quarter of a million victims are buried. Entry is free, the exhibitions are sober and moving, and a visit gives context to everything else you will see in Rwanda.
A private half-day guided tour that strings together the Genocide Memorial, the Kandt House museum, Mount Kigali, the Niyo art gallery and Kimironko Market. The easiest way to see the capital properly with a guide who can explain what you are looking at.
A customisable on-foot tour of central Kigali with a local guide, rated very highly by around a hundred reviewers and priced at a fraction of a car tour. Good for a first morning, for travellers on a budget and for anyone who prefers to see a city at walking pace.
A three-hour walking food tour through Nyamirambo, Kigali's busiest and most characterful neighbourhood, with tastings at local eateries, offered at lunch or dinner. A friendly way to eat your way into Rwandan culture.
Spend an hour with a habituated family of mountain gorillas in the bamboo forests and volcano slopes of Volcanoes National Park. The permit costs 1,500 US dollars, 96 are issued a day and groups are limited to eight, so book early. Rwanda's signature experience.
Full day (trek 30 min to 4+ hours, 1 hour with gorillas)$$$$Book on Viator → Track the endangered golden monkeys through the bamboo forest of Volcanoes National Park. The permit is around 100 US dollars, a fraction of the gorilla permit, and the trek is shorter and easier. A rated-150-times Viator tour adds a cultural experience.
Full day from Kigali (about 1 hour with the monkeys)$$$Book on Viator → A day hike up the Bisoke volcano in Volcanoes National Park to a crater lake high in the clouds, with more than 240 reviews on Viator. The best active option for travellers who want the Virunga volcanoes without a gorilla permit.
Full day (4-7 hours on the trail)$$$Book on Viator → Rwanda's savanna park, about two and a half hours from Kigali, with lions, black and white rhinos, elephants, giraffes, hippos and crocodiles. A one-day game drive from Kigali is the easiest way to add the Big Five to a gorilla trip.
Full day (about 2.5 hours each way from Kigali)$$$Book on Viator → 
A suspension walkway 70 metres above the floor of one of Africa's oldest rainforests. The canopy walk costs around 40 US dollars for visitors, and chimpanzee tracking is Nyungwe's other major draw. A full-day tour from Kigali is available, but a night nearby is better.
Full day from Kigali (about 9.5 hours), or overnight$$$Book on Viator → A half-day adventure on the hill above Kigali: a guided hike up Mount Kigali for city views, then a zipline through the forest. Forty Viator reviews and a from-price around 150 US dollars make it an easy active break in the capital.