Equestria was a different place from Earth. For one thing, it has no humans living in it. Instead, their nation's dominant species were ponies. There were ponies that looked like regular ones from Earth, some with wings, some with horns, and there were 3 with horns and wings. The latter group were the princesses and autocrats of Equestria, and they ruled with benevolence and love for their subjects. They cared for and protected their kingdom through the powers of magic. Magic was a powerful force that existed in Equestria that Earth had almost none of. The two main Princesses used magic to raise the sun and moon. Magic allowed for unicorn race to levitate objects, teleport, and many other feats of physical manipulation. The Pegasi could fly and manipulate the weather. Earth ponies were the strongest of the 3 races and were the best at growing food due a natural connection to the physical earth.
Since its foundation, Equestria was a nation of peace. All the ponies came in different colors, sizes, and breeds, but they respected one another and worked together to bring the kingdom to prosperity. There were other nations ruled by dragons, gryphons, zebras, and other sentient species, and Equestria always made sure that it would maintain peace between them. It has been centuries since any major wars, diseases or famines plagued the kingdom. The nation was vast, and was inhabited by dozens of millions of ponies. Yet there was no overpopulation, revolts, pollution, or ethnic conflicts Equestria needed to deal with. But they realized that their lush, fertile landscapes and ecosystems of nature was at the core. The 3 races were once divided by hatred and resentment for each other, and that in itself destroyed their old homes and almost wiped out ponykind. The ponies wouldn't let that happen to them again. They would share resources and benefit for every pony and for the kingdom.
The human race is a different story. Since its first civilizations, there has been much conflict in the fighting over resources and ownership, even to this day. There were hundreds, perhaps thousands of human civilizations that made them different. Each had its own governments, cultures, religions, customs, and made up of different races of humans that were strange or even frightening to those not part of them. They focused on their differences rather than their similarities. Since trade and industries sprang up, humans were influenced by greed and power. There was little to no magic on Earth, and instead developed advanced science and technology. It greatly increased longevity of the population, communications, agriculture, medicine, and transportation; especially in the past 200 years. But humans were wasteful and polluted their lands, waters, and skies with harmful by-products of these technologies. Crops and livestock declined across the world. Diseases for living amongst them multiplied. Greed for what the resources they owned had increased distrust and hate amongst each other. Humans made destructive weapons that could wipe out whole armies and cities. Even the most powerful of nations were desperate for military and economic superiority. If provoked far enough, they would kill millions and destroy the world just to be on top. Earth was indeed in peril.
Both Equestria and Earth had magical elements that could purify their worlds. Equestria had the Elements of Harmony; composing of Honesty, Kindness, Laughter, Generosity, Loyalty, and Magic. Earth's Elements of Nature included Earth, Fire, Wind, Water, and Heart. When used together, each group could undo the chaos, hatred and pollution that tried to corrupt their land and the people and ponies living on it. Each element's bearer was the living manifestation of that element. The Natural Elements, however could manipulate and generate physical forces of nature that compose their world (Earth, Fire, Wind, and Water) or influence and connect with people to their will (Heart). The Elements of Harmony weren't active like that. They were only used for exhibiting the best qualities of their character. But they were the most powerful forms magic in Equestria. So what happens when the two groups meet?