Potemkin Stairs
...that the Potemkin Stairs located in Odessa, Ukraine create an optical illusion, where either the landings or the stairs are invisible depending on an observer's vantage point?
...that the <b id="mwCXc"><a href="./Potemkin_Stairs" id="mwCXg" rel="mw:WikiLink" title="Potemkin Stairs">Potemkin Stairs</a></b> (<i id="mwCXk">pictured</i>) located in <a class="mw-redirect" href="./Odessa,_Ukraine" id="mwCXo" rel="mw:WikiLink" title="Odessa, Ukraine">Odessa, Ukraine</a> create an <a href="./Optical_illusion" id="mwCXs" rel="mw:WikiLink" title="Optical illusion">optical illusion</a>, where either the landings or the stairs are invisible depending on an observer's vantage point?