In 1995 the European Organization for Nuclear Research (CERN) launched a call for tender for the design and supervision of the civil engineering required as part of the construction of the next generation particle accelerator termed the Large Hadron Collider (LHC). Today, at the end of 2003, over 85% of the construction work has been completed at a cost of around 500 million Swiss Francs. Seven new shafts have been excavated along with four very large caverns and numerous smaller tunnels and galleries. These structures which have been excavated in the weak molasse rock of the Geneva Basin have pushed the design and construction skills of the European tunneling industry to their limit. Detailed design work commenced in April 1996 with three consortiums representing companies from six European states participating. The consultants were selected following a ''two envelope'' bidding process. Construction commenced in March 1998 with all four construction contracts up and running by the end of 1998. Four contracts were awarded for the construction work as detailed in the table below. In addition to these main construction contracts, numerous smaller contracts were also awarded mainly for consolidation works of existing infrastructure as well as specialized works such as site investigation, concrete drilling, etc. Whilst the success of the project has largely due to the skill, determination and hard work of client, designer and contractor alike, some recognition for the success of the project must also be attributable to the contractual framework within which the works were carried out. From the outset, CERN wished to set up a contractual framework that encouraged competitive bidding, enabled fair bidding between companies from various European states, allow quick and cheap dispute resolution and most importantly, were compatible with CERN's specific internal purchase and contract procedures that apply as a result of CERN's status as an international organization. This paper shall discuss the specific Conditions of Contract used for the construction contracts. The development from a standard FIDIC ''Red Book'' contract into four unique contracts shall be explained with the reasons why these modifications and developments were necessary. Lastly, the successes and failures of specific features of the contracts shall be presented and discussed. (A) Reprinted with permission from Elsevier. For the covering abstract see ITRD E124500.