This paper describes a new 2D focus+context visualization technique for viewing and navigating large hierarchical information. This technique uses a semi-transparency approach to display both the global and the detail views of the hierarchy with an overlapped manner in the same display space. The twin views always keep one in highlighted and another in deemphasized, and this state can be shifted interactively when a user focuses on other view. The main advantage of this technique is that there is no geometrical partitioning required and both the context view and the focus view can use the full display space. To achieve the smooth transactions between the views, animation is accommodated to preserver user?s mental map during the navigation. Although this visualization technique can theoretically be applied to many layout algorithms, we only apply this technique, in our implementation, for viewing and navigating hierarchies that are drawn by ENCCON [1] layout algorithm.