Cengiz Holding constructs highways and railways as well as highway and railway tunnels. The Company completed the construction of Ilgaz and Çamlıca tunnels and the construction of Ovit and Zigana tunnels are in progress. Zigana Tunnel, longest in Turkey with a total length of 14,5 km will also be the longest highway tunnel in Europe. Ovit Tunnel is the fourth longest in Europe with a total length of 12,6 km. These projects are managed by Turkish engineers employed by Cengiz İnşaat. Tunnels were built in Sarajevo in line with EU standards by Cengiz İnşaat.