30 years ago, simply being a tattooer was radical; tattooing was still outlawed in many American cities, and tattoo shops were underground hideouts that evaded regulation by necessity. Now, estimates claim that 23 percent of the American population has at least one tattoo, and Instagram has made it exceptionally easy for tattoo artists to share their work with large audiences.

Tattooing has always been a global practice, but the recent growth of the field and the sheer number of people with technical skills have resulted in radical experimentation among those who want to be beyond good; they want to be exceptional. Pushed by the constant evolution of the medium, from the underground to the mainstream, tattooers have increasingly tried to carve out an individual “style” so that customers and clients will travel across countries and continents for an appointment.

The best of them have redefined the medium by putting pressure on rhetorical boundaries that have historically separated tattooing from art or craft. Some have traveled deeper into re-interpreting the cultural roots of tattooing, while others have innovated aesthetically, eschewing some of the visual trademarks that have defined the medium for centuries.

The following 10 tattoo artists, of all ages and nationalities, are some of the innovators breaking the rules and pushing the boundaries of the medium.