you can even see the chisel marks on the walls. >> stahl: doron spielman is the site's international or of development. >> spielman: this is the original old flooring. these are more ritual baths or water cisterns. >> stahl: he led us down to an ancient waterway carved out of the hard stone. >> spielman: the whole beginning of life in ancient jerusalem happened from this little spring which is nestled in this little cave. >> stahl: we were taken down excavated tunnels no human eye has seen for two millennia and shown the process of removing the layers of history, sandbag by sandbag, from when the city was sacked by the romans, and before them, the babylonians. this was the first time i'd ever done an interview in a canaanite fortress. so this structure was here when abraham was here. >> spielman: that's right. he saw it with his own eyes. >> stahl: he saw this. >> spielman: he saw this. >> stahl: that's a bit of a stretch-- archeologists tell us that no one has found any evidence that abraham was ever here. it's controversial that the city of david uses discoveries to try to confirm w