Today, underground development encompasses the relocation of several surface land uses or activities, which are difficult, impractical, less profitable, or even environmentally undesirable to be installed on ground level, into subsurface built environments.This successful heritage should not only be safeguarded but also enriched by establishing a multidisciplinary think-tank group that will allow the incorporation of subsurface space as an integral part of the future physical planning and zoning.

The 11th ACUUS International Conference took place between 10 and 13th of September 2007 at the Lavrio Technological and Cultural Park in Greece. The event was organized by the Laboratory of Mining and Environmental Technology of the National Technical University of Athens. 

The 11th ACUUS International Conference was a very successful and fruitful event having 220 registered participants from 18 countries, who presented 90 scientific papers on various topics. Furthermore, more than 400 people including scientists, engineers and members of the local and governmental authorities attended the conference. During the event the participants had the opportunity to exchange their experience with regards to the utilization of underground space and expand international co-operation schemes that promote research in this field. 

The main topics of the conference technical sessions were: 

• A strategic view of going underground Underground projects
• Experience from the field 
• Underground space utilization in the world 
• Future challenges in underground development 
• Underground solutions towards sustainability 
• Aesthetics and architecture of the underground environment 
• Innovative tools in underground development 
• Feasibility studies of underground projects 
• Public and the underground space 
• Safety and the underground space 
• Improving the underground habitat 

As part of the conference program, a technical visit was organized. The delegates were given a presentation of the construction methods, the problems encountered and other techniques at the construction site of Argyroupoli station of Athens Metro, and later on, they visited the Acropolis metro station with its unique architectural incorporation of archaeological artifacts discovered during its construction. Finally, the delegates enjoyed a tour guide to the archaeological site of Acropolis and the Parthenon.