Celebrating its 25th anniversary this year, Vienna’s Butterfly House is a great place to discover, observe and admire over 500 exotic butterflies in the heart of the city. The building itself is impressive, being one of Europe’s finest Art Nouveau palm houses ever created. Measuring 128 metres in length and a floor area of around 2,000 square metres, it is part of the Hofburg Royal Palace Burggarten grounds, which once served as an oasis of calm and tranquility for Emperor Franz Josef I and his wife Sisi, the iconic Austrian Empress.