Barcelona's excellent transport system includes the metro, buses, trains, funiculars and cable cars; tickets for all (except night buses) are transferable across the system. The metro is the fastest and most efficient way to get around the city, except during the rush hour when it becomes very crowded. The bus network is extensive and is easy to master with a transport map. Night buses take over from about 10pm to 6am. During summer the hop-on hop-off Bus Turistic links all the main sights and tourist destinations. Taxis are plentiful and inexpensive and are a good option especially late at night, but charge extra for a number of things - ask for a receipt. Hiring a car is unnecessary and frustrating within the city, but can be useful if planning daytrips outside the city.