Carstensz Pyramid is one of the Seven Summits. At 4884 Meters (16,023'), it is low compared to the rest, however it is the most technical and quite difficult to access.
Access requires a week's trek through the New Guinea jungle to reach its base. The route requires many pitches of rock climbing up its gullies and corners to reach the ridge. Once there, you can either rappel into a notch and climb out via a 5.8 crack - or pull yourself across on an airy Tyrolean traverse. After all of that, it is still about 2 hours of climbing along the ridge crest to the summit. Descent is reversing the route which makes it a long day!