Walking is the easiest way to explore the compact Old City of Quebec, where most sightseeing opportunities are. Many visitors also enjoy hiring a bicycle and enjoying the city's system of cycle paths.Public buses are run by the Reseau de Transport de la Capitale (RTC), operating throughout the week (there are a limited number of night buses at weekends). Tickets are bought upon boarding with exact change or in advance from newsagents, which is cheaper. Transfers are free within 90 minutes of a single journey. One-day passes can also be bought.Taxis can be hired at the airport, ordered by telephone, or hailed in the street in the centre of the city.