but many only scratched the surface of the city's attractions is also roma subtle rania sub train ian brown. monuments that can be roman monuments that are just as important they allow us to understand how the city of over time. the sub trainee instructions have only opened to the public in recent years. the mithraism of the circus maximus is a religious sign meters underground. at its heart is a relief of the god mithra from the 3rd century b.c. . unfortunately too often we can't offer a broad public access to these spaces because of safety issues or budget limits. or . opening up such spaces to the public is a logistical challenge. some passageways and catechisms have been well explored others hardly at all the culture association sorta ranee i uses modern technology to explore more and more aqueducts shafts chambers and religious relics a remote controlled robot can access spaces too small for people to enter. the last 15 years or so members of the association have been investigating the secrets below the city's streets. volunteering their time out of concern for the fate of the ruins. g

ian brown says he's not going to let that happen again. >> i have beef stock and ingredients sufficient enough to go twice beyond what we expect >> reporter: fake meat often has fewer calories than meat and lower sodium but zero cholesterol and lower fat. these products cost 50% more than meat. they need to convince the farmers to cut out the middle man, the cow, which he says is a less efficient producer of plant protein than his company is. >> it's a five-year program to one category or one product to be able to underprice animal protein in a significant way >> reporter: he said it could take up 10% of the global meat counter and be worth $150 million. but the industry has its work cut out for it >> reporter: would you ever have a meat alternative >> no. >> reporter: why not >> the real thing is the real thing. >>> joining us now from san francisco is brian sweeney he is the president of sweet earth natural foods which has a range of meatless products from burritos to pizza and they are going to introduce a plant-based burger in september. brian, great to have you here. welcome. >> th