The <a href="https://en.wikipedia.org/wiki/Harry_F._Sinclair_House" class="extiw" title="en:Harry F. Sinclair House">Harry F. Sinclair House</a> was built in 1898.  This French Renaissance House was designed by <a href="https://en.wikipedia.org/wiki/CPH_Gilbert" class="extiw" title="en:CPH Gilbert">CPH Gilbert</a> and built for Isaac Fletcher.  It later came into the possession of <a href="https://en.wikipedia.org/wiki/Harry_F._Sinclair" class="extiw" title="en:Harry F. Sinclair">Mr. Sinclair</a>, the founder of <a href="https://en.wikipedia.org/wiki/Sinclair_Oil" class="extiw" title="en:Sinclair Oil">Sinclair Oil</a>.  It is on the southeast corner of the intersection of 5th Ave and 79th St.  It now houses the Ukrainian Institute of America.
<a href="//commons.wikimedia.org/wiki/User:A._Balet" title="User:A. Balet">Andrew Balet</a>
CC BY 3.0
<span class="int-own-work" lang="en">Own work</span>