Sosa-Carrillo-Fremont House is one of Tucson's oldest adobe houses, built around 1880 and home of the Carrillo family for over 90 years. Located on the grounds of the Tucson Convention Center downtown, the house has been restored using period furniture of the 1880s, featuring exhibits of Tucson lifestyles in the 19th century. Admission is free, but reservations are required for walking tours, which are only offered on Saturdays.