"Freedom of speech is supposed to mean the right of everyone to say whatever he likes. But the neglected question is: where? Where does a man have this right? He certainly does not have it on property on which he is trespassing. In short, he has this right only either on his own property or on the property of someone who has agreed, as a gift or in a rental contract, to allow him on the premises. In fact, there is no such thing as a separate ‘right to free speech’; there is only a man’s property rights: the right to do as he wills with his own or to make voluntary agreements with other property owners." - Murray Rothbard 

 And public spaces do not exist?  

 Nope.