The first thing you see when you enter the grounds of the Los Angeles County Museum of Art (LACMA) is Michael Heizer’s Levitated Mass (2012). The boulder weighs 340 tonnes. Several years ago, a custom-made transporter carried it at a speed of seven miles per hour from Jurupa Valley to LACMA–as the bird flies a distance of fifty-five miles, but 106 miles in total to avoid any overpasses too low to allow clearance. Once in the vicinity of the city, hanging street signs and traffic lights had to be lifted and swung out of the boulder’s way. Its slow pace and disruptive size caused a lot of fanfare, and the final miles of its journey attracted thousands of spectators, footage of which you can see on the museum’s website. Now, the boulder hovers in the centre of a long concrete corridor, allowing visitors to walk toward it and then stand beneath it, feeling the energy of the suspended weight above them, imagining how it would feel to be flattened by granite. The first time I saw it, I realized that this is the experience I have of all art that stays with me long after I’ve left the gallery; it has the ability to overtake me, and the tension, the thrum, the movement that the work causes within me is the quiddity of that possibility.