Kronprinzengarten ('Privy', in German called 'crown prince's' Garden); it has 5 pavilions, which I count counter-clockwise from the visitor's entrance. No. 3 was removed in 1960s and replaced by a non-corrosive iron construction in 2002, which is designed as a visual counterpoint and a look-out tower.
<a href="//commons.wikimedia.org/wiki/User:WeHaWoe" class="mw-redirect" title="User:WeHaWoe">Wolfgang H. Wögerer, Wien</a>
CC BY 3.0
<span class="int-own-work" lang="en">Own work</span>