DANILO MALDONADO MACHADO
... El Sexto, is a Cuban graffiti artist and human rights activist* who has been arrested and imprisoned several times by the Castro regime...
His graffiti are a form of protest, criticizing the abuse of the Cuban people at the hands of the Castro regime, and he is "frequently detained by the police under any pretext". He has been called a "graffiti artist who does not forgive the Castro regime". A report in April 2015 stated that he was, at that time, the "the most persecuted of Cuban artists".
You can read more about Danilo's background here.