Flex is really only for teens or a young crowd. If you’re over 30 – this is not your place, but, if you're visiting Vienna and have teenagers, who want to go out a bit on their own, let them get a little crazy here. This place is one of the most popular underground clubs in Vienna, providing an amazing sound system and events with fine artists from alternative rock to electronic music. Every evening has got a different theme, so check out the program on the website. It is located on the Donau canal and the party goes on till 6:00am. In summer, people enjoying sitting outside on the picnic benches in front and chill with friends.