Do jame lahko pridemo peš po označeni poti z belo zelenimi markacijami. Začetek poti je na železniški postaji v Straži, mimo cerkve Sv. Tomaža in nato v gozdnati del hriba. To je del Gozdarske poti, ki pelje do Frate in del Jakobove poti (glej Pešpoti po straškem hribu). Pri jami so postavljene mize in klopi ter manjše ognjišče. Prostor je primeren za piknike.
Ogled jame je možen le v spremstvu jamarjev. Vsako leto sta dva organizirana pohoda do jame in ogled. Prvi je vedno 1. maja, drugi pa v sklopu prireditve Straška jesen, ki poteka konec avgusta prvi vikend v septembru. Datum je objavljen na občinski spletni strani, plakatih in medijih.
Velika Prepadna je kraška jama, ki leži ob gozdni cesti na severozahodnem pobočju Srobotnika. Vhod leži na nadmorski višini 530 m. V grobem je sestavljena iz vhodnega brezna, glavnega rova in spodnje etaže. Vhodno brezno, ki je globoko 24m nakazuje, da se je strop jame udrl in zasul nadaljevanje. Po podornem kamenju se spusti v vhodno dvorano, široko 20m in dolgo 30m. Na desni strani je nizek strop, na levi pa se strmo dviguje do višine 15-20m. Večina sten in stropa so zasigane. V nadaljevanju se dvorana počasi dvigne in preide v podrti rov 2x3m. Tla in stene so lepo zasigane.
Srednja dvorana se razširi in dviga. Tu pridemo do sigovih kop in manjših ponvic. Od srednje dvorane se glavni rov strmo dvigne v zadnji dvorano. Tla so iz zasiganih balvanov, po stenah pa se mešata bela in rdeča siga. V njej je tudi veliko kapnikov, vendar je veliko stalaktitov polomljenih. V dvorani je tudi večji steber, visok okoli 6m in premera 1m, na desni strani pa je 4m globoka razpoka, kjer se nabira voda. Za stebrom sta dve vzpotedni brezni, ki se spojita s Štirno, 20m globokim breznom z zelo razjedenimi stenami, na dnu katerega je ilovica in podorno kamenje - spodnja etaža, ki pa je dostopna le izkušenim jamarjem. Najnižja točka je -95m.
Velika Prepadna je ena redkih vodoravnih jam, saj je pretežno brezno od 10 do 40m globine. Ima skoraj 300m globinskega potenciala.
VELIKA PREPADNA (The Big Abyss)The cave can be reached on foot along the marked path with green-and-white signs. The trail starts at the train station in Straža, past the Church of St.Thomas, and then goes into the forest region of the hill. It is a part of the Forestry Route that leads to Frata and a part of Jacob's Route (see Pešpoti po straškem hribu). Next to the cave, tables and benches are put, and a small fireplace. The place is suitable for picnics.
The cave can be seen only in the company of cave-explorers. Each year there are two organized walks to the cave and visits of it. The first is always on the 1st of May, and the second is within the context of events called the Straška Autumn, which takes place at the end of August, during the first weekend in September. The exact date is posted on the Municipal website, posters and in the media.
Velika prepadna is a Karst cave, lying along a forest road on the northwest slope of the Srobotnik. Its entrance is situated at 530m asl. It consists roughly, of the entrance abyss, the main tunnel and the ground floor. The entry abyss, which is 24m deep, indicates that the ceiling of the cave collapsed and burried the rest. On the remnant stones it drops into the entrance hall, which is 20m wide and 30m long. There is a low ceiling on its right side, while on the left side the ceiling rises steeply to a height of 15-20m. Most of the walls and the ceiling are calcified.
The hall further on slowly rises and reduces into a demolished tunnel of size 2x3m. The floor and its walls are beautifully calcified.
The middle hall expands and rises. There we arrive at the Sinter piles and small Karst pans. From the middle hall, the main tunnel steeply rises into the last hall. The floor is formed from the calcified boulders, while on the walls is red and white Sinter mix. In the last hall there are also many stalactites, though many of them are broken. There is also a big pillar in the hall about 6m high and with a diameter of 1m, and on the right side there is 4 m deep slot, where water gathers. Behind the pillar are to parallel abysses that join with Štirna, a 20m deep abyss with very much corroded walls, at the bottom of which there is clay and remnant stones – i.e. the ground floor, which can be reached only by the experienced cavers. The lowest point of it is -95m.
Velika prepadna is one of the few horizontal caves, as its main abyss is from 10 to 40m deep. It has almost a 300m depth potential.
