Between the lightning and flint, Tang Mubai took out the Taiji Sword and stabbed it in the fourth corner.

The Taiji Sword is not a treasure, but it is better than a treasure.

The yin and yang energy contained in it is only a lot more than the three spirit swords.

If......

"Bang dang~!"

A loud and melodious dull sound came out suddenly.

Tang Mubai, who was worried that the Taiji Sword would not be able to replace the Spirit Sword, saw the huge picture scroll formation in front of him, which quickly swept and rolled and disappeared.

Immediately after, in the position of the original gate pattern pattern, a portal was really opened.

"Whew-"

A wind blew out of the open gate of the cave.

The wind was mixed with dust and a hint of heat.

That's right, Tang Mubai sensed the heat!

The heat is still intensifying, gradually turning into a heat wave.

But the moment before it was formed, it suddenly dissipated, turning into wisps of cool breath floating in the air.

"Whew~"

The "Jewel Dragon" who came over roared and probed his brain to enter the open door.

"Whoosh! Whoosh!"

Silvery white light suddenly floated from inside the portal.

Boom~

Buzz~!Buzz~!Buzz~!

The air currents are circling and the light is gathering.

Inside the portal, silver-white lights quickly formed a cloud of white light.

Under the illumination of these light clusters, the scene inside the door is clearly presented in the field of vision of Tang Mubai and the "Jewel Dragon".

"Whew~"

The "Jewel Dragon" was startled, and its huge body stopped at the door.

Tang Mubai was fearless, and the "Sacred Heart Pass" did not prompt danger, indicating that the safety aspect was still under his control.

Click!

Walk gently and walk through the door.

As soon as I looked around, I saw that there was still dust in the air swirling, and more scattered on the ground.

Obviously, this spacious interior space has been closed for a long time.

In addition to the dust, there were also some bones on the ground that had not been completely weathered, including rusty weapons, collapsed stone platforms, and cracked walls.

All of this shows that there was once a fierce battle here.

As for the final result, Tang Mubai is not clear.

Look around and finish the scan.

Tang Mubai's gaze fell on the corners and several formations in the central area.

These formations are glowing, emitting a silvery-white glow, illuminating the entire space.

The bright underground space is as large as a football field.

In addition to the four square formations in the central area, stone houses have been built on both sides of the edge.

Through the open door panels of unknown materials, there is also a bright light coming from the interior of the stone house.

Tang Mubai was curious and walked over.

I chose a random stone house to enter, and the first thing I saw was the source of the light.

A circular formation with not many lines!

This formation is still quite familiar to Tang Mubai.

"Gathering Array?"

Gather the energy of heaven and earth in one point, so that it is convenient for martial artists to absorb and refine.

This kind of single-room room with a "gathering array" has a popular name.

Training room!

It's not a practice room left by Tang Mubai's father, it's just a closed space with better sound insulation.

The real cultivation room has a "gathering array".

Martial artists only need to sit on the "gathering array" and run martial arts.

The speed of condensing qi and blood is faster than absorbing the energy of heaven and earth outside, or devouring qi and blood pills, ferocious beast flesh, and ordinary elixirs!

As far as Tang Mubai knows.

Even if it is the lowest-level "Gathering Energy Array", a martial artist can sit on it and practice for one day, which can be worth ten days outside for others!

Those big forces cultivating disciples are basically equipped with cultivation rooms.

The "Gathering Energy Array" in the stone house in front of him, Tang Mubai carefully identified it and determined it to be intermediate.

Although it is not advanced, the speed of operation is very fast, and it has only been a while since Tang Mubai came in, and the energy of birth is already comparable to that of some special regions.

If the "Gathering Array" is allowed to run, the breeding energy will only increase!

And such a cultivation room, Tang Mubai just glanced at it roughly, nearly forty!

"So, this place is not a treasure house, but a cultivation ground?

Tang Mubai, who had sorted out his thoughts, was a little happy and a little disappointed at the same time.

It was so difficult to open the formation at the entrance, and there were only cultivation rooms inside.

The big guy who opened up this underground space, should he be so capricious?

Tang Mubai sighed, somewhat unwilling.

In order to crack the formation, he deliberately went to the Fifty-Nine Domains to learn the formation.

As a result, after opening the entrance, I only got the cultivation room, but no treasures, so I was unwilling!

Walking out of the stone house, Tang Mubai carefully scanned the huge underground space, hoping to find treasures hidden in relatively hidden places.

It's a pity that I scanned the entire underground space back and forth several times, but I couldn't find it.

The "Sacred Heart" also has no hints, which shows that there are really no treasures here!

There was a sloping down staircase, which Tang Mubai found in the corner.

Descend the steps to the next floor, and as a result, there are also cultivation rooms below.

Different from the upper layer, there are more than a dozen cultivation rooms on the lower floor, and the cool breath wafting in the air is stronger, and the "energy gathering array" arranged in each cultivation room is larger, and the energy is more generated.

And that's not all.

In the second layer of space, after a careful search, Tang Mubai once again found a staircase leading to the bottom!

Walk down the steps to the third floor of the space, and sure enough, there is also a cultivation room on this floor.

The difference is that there are only three cultivation rooms in this space.

The "Gathering Energy Array" arranged in each cultivation room belongs to the advanced formation, and the condensed energy concentration is higher, the speed is faster, and the content is more!

The cool smell in the air is also richer than the two layers above.

It's just that the heat in the third layer of space has not completely dissipated, and there are still residues.

If you stay here for a long time, the average person will not be able to stand it.

Tang Mubai was not afraid, turned on the "temperature control" supernatural power, and carefully sensed the source of heat.

It turned out that all the heat came from underground!

The starting point of the "Gathering Energy Array", the source of the connection of the formations, is also located underground!

"Is geothermal energy?"

Tang Mubai simulated all the formations in the three-layer space in his mind, connected together, forming a "gathering array".

Confirm the source of all the "energy gathering arrays", and sure enough, they come from geothermal energy!

The unknown forces that have opened up the third layer of space, or the big guys, have set up a cultivation room here.

Not surprisingly, it's because of the geothermal energy here.

Underground thermal energy also belongs to a kind of heaven and earth energy, but after countless years of earth evolution, it has long been biased towards fire attribute energy.

The dozens of cultivation rooms in the three-story underground space changed the fire attribute energy into non-attribute energy through the change of the formation.

After all.

The former is only suitable for cultivating fire-attribute martial arts, while the latter can be absorbed by everyone!

In addition......

"Huh, there's someone in this training room?"