The city-centre can be explored easily by walking. If one wants to get around quickly one may purchase  travel cards for one or more people which permit unlimited travel by tram, bus and local railways. All operate frequently. The city itself is getting greener year by year - literally. Tens of thousands of trees have been planted, public gardens and parks created or reconstructed. The city is not grey any longer but full of colour. Recently the "Hundertwasser-House" or "Green Citadel" has been completed. Not everyone likes it - but is is impressive.