Oh, so now it's EXPERT witnesses that must be presented to impress atheists! How about just a few plain, ordinary witnesses? Tacitus was not born until after Jesus was crucified. He never saw Jesus. But are you suggesting that any historian must have witnessed the events he writes about in order to be believed? Does that mean you only read the history of the First World War by people who wrote about it while it was happening?

Over 500 people witnessed Jesus Christ alive after He had been crucified. Or do you think any Court of Law in the first century would refuse to consider their testimony, just because the Judge had never seen this Jesus himself? I am so glad you are not a member of the Judiciary.

Now, let those who insist that history discounts the existence of Jesus of Nazareth produce their competent (let alone expert) historians who offer the necessary proof as to the non-existence of Jesus.

Notice that lack of mention about events relating to Jesus by certain individuals of His era can never be taken to mean those events never happened until we are satisfied that everything those individuals ever wrote has been dug up and translated. Nor can just a tiny amount of written documentation be called upon as evidence that certain events never happened. For example:

Thycydides' History of Peloponnesian War was originally written around 430 - 400 B.C. The oldest surviving copy is dated to AD 900 and there are only a few first century fragments, with about 400 years between the original and the fragments. Only 8 copies exist today. Does this mean to say that we should insist Thucydides was wrong in claiming this war happened?

Take Caesar's Gallic War, originally written about 52-52 BC. The oldest surviving copy is AD 850, giving a 900 year gap between the original and the oldest copy - only 10 copies exist. Should we dismiss the Gallic War due to such scant written records?

The Four Gospels about Jesus Christ were written between AD 65 and AD 90 (from 30 years after his death) and there are hundreds of thousands of manuscript copies of them. Yet some people think they should all be dismissed because certain non-Christian writers don't mention Jesus. Well, Pliny (who executed some Christians around AD 100) did, as well as Josephus (AD 37-100) who was an official historian. Further, the Jewish nation has never disputed the existence of this Jesus of Nazareth. They only dispute the claim that he was the promised Messiah. They are the collective elephant in the room you need to look at.

In a 2011 review of the state of modern scholarship, Bart Ehrman (who is a secular agnostic) wrote: "He certainly existed, as virtually every competent scholar of antiquity, Christian or non-Christian, agrees" B. Ehrman, 2011 Forged : writing in the name of God ISBN 978-0-06-207863-6. page 285.

They were Paleosiberians. (from modern day Russia and Mongolia) They only became Paleo-Indians after settling in America.

I don't think they can be said to have really "discovered" America as such as the term in the exploratory sense didn't exist. They had no real idea of what existed beyond their hunting ranges in any direction, other than what some other tribe might have described to them. The old world of Asia across which their ancestors had slowly spread was as much a mystery to them as was the North American continent ahead.
Humanity began in East Africa and any land beyond there is a place humans have migrated to, and is not a natural human habitat. We don't hail the human discovery dates of Europe, or Australia or any other migratory event and America is no different in that respect.

Moving down into the Americas from the Beringa land bridge was something they did in search of new foraging opportunities and probably following prey animals. They weren't tracking in thinking "Woah, dudes, we found a whole new continent no human has ever set foot in before!" They were thinking "The moose went this way! Lets follow him!"

Let me use David as an example here.

What a lot of people call "American culture" and rant about is actually the "new global culture."

Take McDonalds. McDonalds isn't "American" it is just cheap food, fast sold using the franchise system. Is this an invention from America? Sure, but it isn't American culture. Spending less money on food? Who doesn't like that? Spending less time on lunch? How is that a bad thing? Having that food meet a certain minimum standard of quality? Also a good thing. A franchise just replicates what has been successful over and over. So you don't have to eat the really crappy, expensive food. McDonalds doesn't replace a restaurant, unless that restaurant sucks. So when some people rant about "American Culture" they just mean "any way that is different from the way it was done in my country fifty years ago."

Much of "American culture" isn't made in America. It just means "movies and music made for the English speaking audience" which the rest of the world steals and watches for free and if you live in a wealthy country, they make translations of. Japan for instance, despite being a small country gets a lot of product made for it. This stuff gets translated into English as well. Much of the "new global culture is produced overseas. Anime is global culture. Hong Kong kung Fu movies are global culture. Harry Potter is global culture. Prada is global culture. Swedish Produced pop music is global culture.

Yahoo is an example of this. Yahoo's prime revenue streams come from America and the English speaking world. Lesser revenue streams come from the rest of the West, such as Japan and Europe. Yet every third world computer jockey has a free email account. This is replicated throughout the media. They sell the product to Americans, the Japanese, and Brits, but the rest of the world watches it because their own "culture" doesn't churn this stuff out. There is little cash today in selling internet ads to Somalis.

Most rants about "american culture" are just rants about the modern, globalized world.

You hear them from Americans all the time. People who hate anything popular.

There probably would not have been any Parthian or Sassanid empire - the Achaemenid dynasty would have continued to rule the Persian empire.

An Achaemenid conquest of Greece would have meant no Macedonian invasion of the Persian empire by Alexander the Great,and it was this invasion that ended the Achaemenid dynasty.

The Achaemenids were severely weakened by their failure to conquer Greece,Xenophon mentioned in his 'Anabasis' (an account of a Greek mercenary force that fought at the battle of Cunaxa in 401 BC in support of Cyrus the Younger,who was attempting to seize the Persian throne) that the Persian empire could belong to anyone strong enough to take it,so weak had the Achaemenids become due to infighting and over ambitious satraps.

All this would never had happened had Darius or Xerxes conquered Greece in the early 5th century - the Achaemenid empire would have become stronger rather than weaker,Alexander would never have conquered the Persian empire,and the Parthians (a successor state to the Seleucid empire as that polity weakened) and thus the Sassanid empire (the Sassanids overthrew the Parthians) would probably never have come to power.