TeraGrid, the US supercomputing cyberinfrastructure, and DEISA, the corresponding European supercomputing grid infrastructure, have been linked, for the purposes of a technology demonstration, by a common, scalable, wide-area global file system spanning two continents, by a common, scalable, wide-area global file system spanning two continents. The bridging of communities in the old and the new world were showcased during the Supercomputing Conference SC05 at Seattle. It was shown that any scientist, accessing TeraGrid from any of the participating sites in the US, or accessing DEISA from any of the DEISA sites in France, Germany or Italy, can directly and transparently create or access collaborative data stored in the now linked grid-wide global file systems of TeraGrid and DEISA with one common file address space. The even more important aspect is that the same is true for applications which, executed at any of the participating sites, transparently access data in the common file address space. High performance wide-area global file systems as GPFS from IBM open totally new modes of operation within grid infrastructures, especially in supercomputing grids with a fairly limited number of participating sites. A common data repository with fast access, transparently accessible both by applications running anywhere in the grid, and by scientists working at any partner site as entry point to the grid, greatly facilitates cooperative scientific work at the continually increasing geographically distributed scientific communities. Both DEISA and TeraGrid have begun using the high performance wide-area global file system GPFS from IBM in production mode. For the technology demonstration, the dedicated DEISA and TeraGrid networks were interconnected with the help of specialists from GEANT, Abilene/Internet2, and the national research networks from France, Germany, and Italy (RENATER, DFN, GARR). They established a two continent spanning high performance network between TeraGrid sites at The San Diego Supercomputer Center (SDSC), Chicago, and Indiana, and DEISA sites in several European countries (France, Germany, Italy). Over this dedicated connection, DEISA and TeraGrid global file systems were merged into one common global file system. This network connection between the two infrastructures is expected to become persistent at some time in the future. The demonstration featured the execution of supercomputing applications of various scientific disciplines which were carried out both as TeraGrid and as DEISA applications. Single site applications transparently wrote their results to the intercontinental global file system, ready for transparent further processing from other access grid access points. Featured applications for the demo included a Protein Structure Prediction and a Cosmological Simulation carried out at SDSC, US and a Gyrokinetic Turbulence Simulation and also a Cosmological Simulation carried out at Garching Computing Centre of the Max Planck Society (RZG), Germany.