Why does the world have borders?

To figure out why the world has borders, we should have to know what borders are for.

After the 9/11 attack, the borders and the border patrol were strengthened to prevent any other attack like that so it wouldn't happen again. Borders can be used for safety and protection, but they can also be used for separation and isolation to other countries which might cause racism to other people from other races and places.

But why do we have to have borders? We were taught that all people were the same and that we should all be treated equally. So why do we really have to be seperated and why are they so strict to not let anyone else in? When we think of borders one of the first things we think of is protection, because again we don't want another terrorist attack to happen again.

But from a perspective from another country, I think in the Philippines, they don't have so much to worry about borders so much because it is an island, and to get there you can't just hop a fence. But you still need a visa and a passport just like if someone in Mexico was trying to come to the US.

To some, a border is just an invisible line where very different people can live. To others, it can be somthing that they believe shouldn't be messed with.