There are these ancient Vedic texts (Hinduism) that explains about 4 eras
The first era was long time ago, very long time, and people were bigger, long lived and everything was really big. Thing is that all these Dinosaur bones we find now are the remains of the reptiles you find in your backyard but from that era, yes, that big. Read below. Full books are free online with original Sanskrit and translation.
The duration of the material universe is limited. It is manifested in cycles of kalpas. A kalpa is a day of Brahmā, and one day of Brahmā consists of a thousand cycles of four yugas, or ages: Satya, Tretā, Dvāpara and Kali. The cycle of Satya is characterized by virtue, wisdom and religion, there being practically no ignorance and vice, and the yuga lasts 1,728,000 years. In the Tretā-yuga vice is introduced, and this yuga lasts 1,296,000 years. In the Dvāpara-yuga there is an even greater decline in virtue and religion, vice increasing, and this yuga lasts 864,000 years. And finally in Kali-yuga (the yuga we have now been experiencing over the past 5,000 years) there is an abundance of strife, ignorance, irreligion and vice, true virtue being practically nonexistent, and this yuga lasts 432,000 years. In Kali-yuga vice increases to such a point that at the termination of the yuga the Supreme Lord Himself appears as the Kalki avatāra, vanquishes the demons, saves His devotees, and commences another Satya-yuga. Then the process is set rolling again. These four yugas, rotating a thousand times, comprise one day of Brahmā, and the same number comprise one night. Brahmā lives one hundred of such “years” and then dies. These “hundred years” by earth calculations total to 311 trillion and 40 billion earth years. By these calculations the life of Brahmā seems fantastic and interminable, but from the viewpoint of eternity it is as brief as a lightning flash. In the Causal Ocean there are innumerable Brahmās rising and disappearing like bubbles in the Atlantic. Brahmā and his creation are all part of the material universe, and therefore they are in constant flux.
This chapter discusses the four kinds of annihilation (constant, occasional, material and final) and the chanting of the holy name of Lord Hari, which is the only means of stopping the cycle of material life.
One thousand cycles of four ages constitute one day of Brahmā, and each day of Brahmā, called a kalpa, contains within it the lifetimes of fourteen Manus. The duration of Brahmā’s night is the same as that of his day. During his night Brahmā sleeps, and the three planetary systems meet destruction; this is the naimittika, or occasional, annihilation. When Brahmā’s life span of one hundred years is finished, there occurs the prākṛtika, or total material, annihilation. At that time the seven elements of material nature, beginning with the mahat, and the entire universal egg composed of them are destroyed. When a person achieves knowledge of the Absolute, he understands factual reality. He perceives the entire created universe as separate from the Absolute and therefore unreal. That is called the ātyantika, or final, annihilation (liberation). At every moment time invisibly transforms the bodies of all created beings and all other manifestations of matter. This process of transformation causes the living entity to undergo the constant annihilation of birth and death. Those possessed of subtle vision state that all creatures, including Brahmā himself, are always subject to generation and annihilation. Material life means subjugation to birth and death, or generation and annihilation. The only boat suitable for crossing the ocean of material existence, which is otherwise impossible to cross, is the boat of submissive hearing of the nectarean pastimes of the Supreme Personality of Godhead.
There are these ancient Vedic texts (Hinduism) that explains about 4 eras
The first era was long time ago, very long time, and people were bigger, long lived and everything was really big. Thing is that all these Dinosaur bones we find now are the remains of the reptiles you find in your backyard but from that era, yes, that big. Read below. Full books are free online with original Sanskrit and translation.
https://vedabase.io/en/library/bg/8/17/ -- Bhagavad Gita (Gitopanisad)
https://vedabase.io/en/library/sb/12/4/ -- Srimad Bhagavatam (Bhagavat Purana)