18.000 m² building includes a 800-people cafeteria, 250-people auditorium/multi-purpose hall, meeting halls in different sizes and about 9.000 m² of office area. HAS Mimarlik’s interior design works were coordinated as the architectural-engineering design of UMO was being prepared.

Main idea of the interior design is to satisfy the employees' longing for "green". Stylized "green" elements are also used as a sign and symbol of the public areas.  The green environment starts at the entrance, follows the atriums and ends in the cafeteria. Specially designed moving “leaves” are treated as mobile sculptures.