After talking for a long time, Ye Fei finally understood that this type of city wall with Mysterious Mechanism Camp could not be replicated, unless the Miracle Continent could find a second Iron Sand Mountain. Furthermore, even if they could find Iron Sand Mountain, building a city wall around the size of Mysterious Mechanism Camp would be alright. If they wanted to use the city walls to surround a city, it was probably not enough to build Iron Sand Mountain!


    After all, the entire Mysterious Mechanism Camp was much smaller than a city. The walls surrounding the Mysterious Mechanism Camp were only ten kilometers around the city walls.


    However, under Ye Fei''s persuasion, Ye Xiaozhang still helped his grandson keep the matter of the city walls a secret. When he reported it to Lan Qizhan, Ye Xiaozhang simply passed it by, saying that the city walls that had been burnt through had become much sturdier.


    After all, besides Ye Xiaozhang, the Empire would not be able to find another Martial God who would appear on the surface. Furthermore, there would not be anyone who would waste their time testing the toughness of the city walls. Therefore, this matter was covered up just like that!


    No one could imagine how many people had suffered on this steel wall. Even Ye Xiaozhang did not expect that, not only was this steel wall sturdy, Ye Fei had even tampered with it, to the point of calling it the never-ending Death City Wall!


    A few days later, the Mysterious Mechanism Camp soldiers all returned, and began their normal training and living. It had to be said that Ye Fei''s luck was very good. Originally, Ye Fei had designed several sets of crossbows, and whether it was stability or range, they were all much stronger than the crossbows that his Miracle Continent had originally been!


    However, what troubled Ye Fei was that he needed to find a blacksmith to create these crossbows. However, if he were to use a blacksmith to forge it, Ye Fei believed that the process would be leaked out soon. Of course, the most important thing was the construction of the hot air balloon parts!


    However, when Ye Fei and the generals of Mysterious Mechanism Camp talked about this issue, all the generals laughed!


    It turned out that in this war of endless Miracle Continent, ordinary commoners, in order to survive, would generally choose to plant and weave their land, while males usually chose to forge iron as their source of livelihood!


    In other words, other than Ye Fei, the rest of the fifty thousand soldiers could all wield a large hammer and do the work of blacksmiths. There were even a few soldiers who, because of their ancestors who were blacksmiths, learned how to forge iron from young.


    With Ye Fei''s order, the time for the Mysterious Mechanism Camp Warriors to run around the Iron Sand Mountain changed to the time for them to forge iron. For a period of time, the people outside the city walls would hear the sound of metal clanging everyday!


    Finally, under Ye Fei''s command, the first hot air balloon of Miracle Continent was born! The entire hot air balloon was made with 20 pieces of water ox skin. Under the hot air balloon, there was a large basket that could accommodate 30 people. The ignition material was made from the most abundant oil of the continent!


    The rise and fall of a hot air balloon depended on the size of the flame jet! Ye Fei did not have the ability to create a flamethrower, but that did not mean he could not create a blower!


    There was a human blower connected under the hot air balloon''s flameout port, and the power of the blower was 4 Ye Fei''s bikes that were similar to the ones used on Earth. As long as the four warriors tread together, the speed at which the hot air balloon would rise would be extremely fast!


    A hot air balloon could accommodate thirty soldiers, which made it a small team. The entire team of soldiers will take turns to give the blower power, which will allow the hot air balloon to soar in the sky until the oil and fire runs out!


    The 28th of September 15601 Miracle Continent calendar. This was a day to excite the entire aristocracy of the Empire, because this day would be the day when the Mysterious Mechanism Camp of the Imperial Air Force would rise to the sky. And the first passengers of this hot air balloon would be General Ye Fei and the five division and battalion commanders of the Mysterious Mechanism Camp!


    Originally, had been advised not to try it out, even though it included Lan Qizhan, the empire''s aristocrats, the entire Ye Family, and all the soldiers of the Mysterious Mechanism Camp were also advised not to.


    However, Ye Fei did not listen to her advice and insisted on being the first to try it out. His words were as such: "This hot air balloon was designed and created by me, so if there are any risks, I must be the first to bear them. I do not have the habit of letting my soldiers bear the risks for me.


    Naturally, Ye Fei''s words further deepened the respect and reverence the officers had for him. But no one knew that Ye Fei himself had no other choice, as the first to eat this crab must truly be him!


    This was because two years ago, when Frelot asked him in the Main Palace about how to control the direction of the hot air balloon, he swore and added that it was a secret.


    But in reality, Ye Fei really didn''t know how to control the direction of the hot air balloon! He only remembered that back on Earth, the person who used to use the hot air balloon said that the direction of the hot air balloon was determined by the height he ascended to!


    After all, at that time, Ye Fei was Earth''s one and only super Free Immortal. Forget about hot air balloons, even supersonic fighter jets would not be able to catch up with him in terms of flying speed, so Ye Fei had only heard of him before.


    Therefore, Ye Fei had to go up on stage personally. As a former Free Immortal, Ye Fei was much more sensitive to air movements, and only after personally practicing using the knife would he be able to have a specific understanding of how to control the hot air balloon''s flight direction. Only after returning would he be able to teach the soldiers of the Mysterious Mechanism Camp!


    Under the fervent gazes of Lan Qizhan and all the nobles, Ye Fei brought the five Battalion Commanders up onto the hot air balloon.


    After igniting the fire, the other four Battalion Commanders sat on the four pedals and quickly used all their strength to climb onto the pedals. Not long later, under everyone''s expectant gazes and exclamations, the hot air balloon slowly flew up with Ye Fei and the others, and slowly flew off into the distance.


    The speed of the hot air balloon was neither fast nor slow! Soon, everyone could no longer see the hot air balloon! And at this time, the one who was the most excited was none other than Emperor Lan Qizhan!


    Although the hot air balloon was no longer visible, Lan Qizhan''s gaze was still floating in the sky, unable to be retracted. He continuously muttered: "This is our Mysterious Mechanism Camp, this is our Air Force! I … There''s an air force now! "


    Fox hurriedly sent flattery from the side, "Congratulations your majesty. With the first batch of Air Force from the gods and devils, your majesty will definitely become the greatest emperor of all time!"


    At this time, Lan Qizhan seemed to have thought of something, and retracted his gaze and looked at Ye Xiaozhang: "Old Marshal, did Ye Fei say before he left, when they would be back?"