Meteorite Impact or Volcanic Crater?

Meng Chao and the exploration team set up a circle of firing points near the transmigration portal, forming a small jungle fortress.

They also planted a large number of mines outside the fortress.

Last time, one of Lu Siya's small teams had also mysteriously disappeared behind the minefield.

This time, in addition to the mines, they also installed a large number of time-delayed crystal bombs.

Such bombs required the humans to send a safety signal every once in a while in order to delay the detonation time.

In the event that something bad happened to them, the bombs would automatically detonate. They would then released smoke produced by the friction of the crystal powder, which would provide the most eye-catching fire guidance for the railway guns that were dozens of kilometers away.