Ayvaini Cave

Ayvaini Cave is the sixth longest cave in Türkiye and is located within the boundaries of Bursa Province. One entrance of the cave is near Ayvaköy, which belongs to the Nilüfer district, while the other entrance lies between the villages of Kazanpınar and Doğanalan, both under the jurisdiction of the Mustafakemalpaşa district. The cave is situated south of Lake Uluabat and has an active hydrological system. Underground waters emerge at the surface through the entrance near Ayva Village. The cave is approximately 5.5 kilometers long.

^{Ayvaini Cave (}Nilüfer District Governorship, Republic of Türkiye⁾

Ayvaini Cave is a karstic system developed within limestone formations dating to the Mesozoic Era. The cave was discovered in 1970 by a three-member Spanish caving team. Morphologically, it has a horizontal development pattern with entrances at both ends. The distance between the two entrances is approximately four kilometers.

The Karadonlu Stream flows through the cave, forming more than 60 small and large ponds along its course. Numerous stalactites, stalagmites, and travertine formations are observed within the cave’s interior. These structures have developed naturally as a result of the hydrological and chemical processes occurring within the cave’s microsystems.

^{Ayvaini Cave (}Nilüfer District Governorship, Republic of Türkiye⁾

Due to the steep terrain surrounding the cave entrances, it is closed to tourist visits. However, it is used by professional climbers and cavers for research and transit purposes. A stabilized path leading from Doğanalan Village to the cave’s starting point extends approximately two kilometers in a northeast direction. Doğanalan Village is about 12 kilometers from Söğütalan.

Access to Ayvaini Cave is possible via the old road connecting Bursa and Mustafakemalpaşa. The cave lies near this route. Although this provides certain logistical advantages, the nature of the entrance points restricts usage to individuals with specific expertise only.