Iran, the land of Aryans who migrated to Iran plateau from 5000 years ago. Aryans lived in the south of Siberia. Due to some reasons like lack of grass for cattle and the harsh climate in southern Siberia (current Russia). In the beginning, the migrants had some challenges with the aborigines of Iran. Then they united to fight against some invaders like Assyrians. About 2800 years ago, the Median Empire was established. You can visit some ruins of that period in current Hamedan.
This post by CNN gives you a good chronology of Iran in the current century. We had lots of ups and downs like regime change, the longest war of the 20th century, and Iran-USA serious tensions last 50 years. Therefore, some travelers thought it would be better not to take the announced risks by the ministry of foreign affairs of their country. Although, some adventurers started to travel and it was so strange to feel the real Iran opposite of what they heard in the media. Finally, it convinces them to introduce Iran to their friends and family and come back to visit Iran again.
In this video, you get some general information about Iran that would better to know before traveling to Iran.