By religion, do you mean faiths? Like Christian, Muslim, Buddism, etc.? The beliefs for each are so different that I don't think it is possible right now. If you mean denominations, like Catholic, Baptist, etc., possibly, but unlikely.
However, after the rapture when all the Christians are gone from the earth, it will happen that there is a one world religion.
Revelation in the Bible talks about such a time. It isn't referred to in a positive way. You'll basically be required to follow this religion and eventually to pledge allegiance to the antichrist and take his mark in order to be able to buy or sell anything. Those who become Christians after the rapture will be considered enemies of the state and will be tortured, killed, beheaded.
I have a tendency to read the last few pages of a book first, because if the ending isn't exciting or what I like, I don't waste my time reading it. So, when I first started reading the Bible, I started in Revelation. That book of the Bible really blew my mind, but it is very interesting and a lot of prophecies, like Israel becoming a nation again, have come true already.
Anyway, just my two cents. As I've quickly learned, there are some on these boards that will attack any Christian perspective whatsoever and I refuse to get down and wallow in the mud with them. Their arguments will never shake my faith. They could present me with "evidence" and I'd know it was a hoax. My faith is that firm. However, I think your question was sincere, so I thought I'd share my perspective.