<a href="https://en.wikipedia.org/wiki/Eadweard_Muybridge" id="mw1g" rel="mw:WikiLink" title="Eadweard Muybridge">Eadweard Muybridge</a> takes <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Sallie_Gardner_at_a_Gallop" id="mw1w" rel="mw:WikiLink" title="Sallie Gardner at a Gallop">a series of photographs</a> to prove that all four feet of a horse leave the ground when it runs; the study becomes the basis of <a href="https://en.wikipedia.org/wiki/Film" id="mw2A" rel="mw:WikiLink" title="Film">motion pictures</a>.