| In the classification of fungi, the truffle is placed in the category of hypogean Ascomycetes. |
| The composition of hypogean and epigean species is used to study the structure of karst aquifer in typical sites of Southern and Eastern France. |
| Mostly they have been provided, because of their polifunctional use, with ovens, chapels and even with hypogean oil-mills, becoming that way some real jewels of country architecture. |
| During the restoration, ancient archaeological findings have been brought to light, such as hypogean granaries and wells, stone mangers and drinking troughs. |
| In the area underneath the Roeroexpo small square there is a 1200 m2 room. At the moment this hypogean space hosts a multifunction-room equipped with two small rooms for direction and translations and 120 seats. |
| Hypogean fishes have always been a source of amazement and amusement throughout the history of ichthyology. |
