I don't feel like I need to go into depth explaining why the Bible is utterly unreliable as a history book. In any case, here is what I consider to be one of the strongest criticisms of the 'good book' and its historicity.
It has been shown by archaeology that the Old Testament (almost in its entirety) was composed at the very earliest, during the reign of Josiah. Josiah was King of Judah between 641 and 609 BCE, and many of the events described within the Pentateuch are supposed to have occurred around 4000 BCE. Here are a few anachronisms that place the limit of date composition to the mid first millennium.
-Camels are mentioned in the Patriarchal Narratives as used by Arabian Traders, and the products they were carrying "gum, balm, and myrrh", as these products were not traded and camels were not used in the area until well after 1000 BCE.
-Isaac encounters the Philistines in Genesis 26, but the Philistines didn't even enter this area until after 1200 BCE. (several-thousand-year discrepancy there)
-The names of several cities are recorded as being destroyed by Joshua, but the majority of these did not exist at the time. Including Jericho, Ai, Gibeon, Lachish, Hazor and many others. The ones that did exist at the time were not destroyed during the timeline of Deuteronomy.
In fact the entire history before ~1200 BCE written in the Old Testament is like a complete fabrication, as all evidence points towards the Israelites only appearing in Palestine around this time, and it is most probable that the Israelites were simply a sub-group of Canaanites, but that's an issue for another day.
What fascinates me with the historicity of the Old Testament the most, is that Jesus, as attributed to him in the Gospels, speaks as if Abraham and other Old Testament characters were really historical figures. Christians believe that Jesus is actually God, yet he doesn't seem aware that the people he speaks about are fictitious.