I had never heard of the Amsterdam Underground Festival, but fortunately as a Trippist, I'm privy to some good tips from the powers that be. Starting September 27th, and lasting for 4 days; Amsterdam will open up some of its least known and unique underground spaces for art, dance, theater, and music.

Reading through the list of venues, I'm finding it hard to resist the chance to walk in spaces that may never again be open to the public in this manner. They include:

• A secret tunnel under the Ij (inner harbor) - Now it is common knowledge that you can drive under the Ij through the tunnel under Nemo. But apparently there's a second tunnel that is not normally used, but will be open to festival goers while featuring a special art exhibit.
• The Caison 1 tunnel - access tunnel to the new North South metro line that cuts right through the heart of Amsterdam. Soon it will be the exclusive terrain of subway cars, but not before being open to the public ONLY during the underground festival.
• Amsterdam's smallest bridge cellar. What's a bridge cellar? Nevermind that, just know that normally they're not accessible to regular people and on this special occasion, you can dance the night away there.

Prices for the events vary depending on what you want to see. But each ticket comes out to be under 10 euros, pretty good price for getting into such special places. Tickets are available now for purchasing online on their website, where you can also read additional info and get directions to each underground gem.