since, it's been known as hadrian's wall. it runs east to west for about 70 miles, starting almost at the north sea and ending at the irish sea. the height of the wall varied. at its highest point, the wall rose up 20 feet above the grassy land. it took 16,000 roman soldiers 10 years to build. historians argue over just why the wall was built. some believe it was a barrier to separate roman-controlled britain on this side from the wild barbarian tribes on the other side. another theory was that by building a wall with gates and checkpoints, it allowed the romans to collect taxes on those passing through. or it could have just been built to show off the power that was rome. whatever the reason, forts were built along the wall and manned by soldiers. these are the remains of one of the bigger forts. as the years passed, the romans left england and the soldiers left the wall. in later centuries, many of the stones were taken from the wall to build roads. this important part of history would have been lost if not for a man by the

when the emperor, hadrian, builds a pagan temple over the site and ends up marking for all posterityf his death. >> the year before helena's son, the emperor constantine, ordered the temple be torn down. >> it wasn't his policy to destroy all of them, but that temple was the very antithesis of what christians thought christ was about. >> the account of what happened next is recorded in a later church history. >> at some point, perhaps as early as the 360s, we begin to see a legend emerge that describes helena's role in the finding of the true cross. >> which hold helena personally with her own bare hands removes some of the earth and uncovers three wooden crosses jumbled together. >> when she came across what she thought was that relic, one can only imagine the emotions that welled up inside of her. ♪ >> the reality is that we don't know precisely what happened in jerusalem. and my own personal belief is that helena found something that she believed to be the true cross. next. ♪ expected wait time: 55 minutes. your call is important to us. thank you for your patience. waiter! vo: in