announcer: you are watching live coverage of the gettysburg college institute on american history tv. hisarmichael talking about -- survived. over the next 10 minutes, we will visit the c-span cities tour. right now, i am standing in windsor across the detroit river is the city of detroit. next, our look at the city continues to explore the border crossing between canada and the united states, the busiest in all the country.

>> the city of detroit and windsor is not just -- canada and america, the biggest trade 2rtners in the world, connect billion and trade world for both countries. were a network of transportation in international trade, and important part of our history and has been pre-civil war. of allprohibition, 75% in this country for the 14 years of prohibition and neighbors from the south. trade in 1800s in detroit was guardcity usa, the

capital of america. we were not only transporting and raw materials. there were days in 1860's where you had 7000 railroad cars waiting to be transported that could not get across the river because the train would have to wait for fairies -- ferries. that made the conversation about either return a lorry bridge -- a tunnel or a bridge. it had to be done because we had storehouses filling up waiting for this transportation that was ferries because ferries can 60 cars at at time. as detroit grows during the civil war, we need an infrastructure that supplied taking from canada and hitting over to detroit and vice versa. , we have two tunnels

under the detroit river. one for train transport. in 1910, it took four years to build at a cost of $85 million. in 1930, president hoover rings a bell, simultaneously in detroit opens the detroit windsor tunnel. at just shy of a mile, it is the tunnel.derwater it has been operating seamlessly since that time. 1990's.novation in the -- $60 million renovation in the 1990's. railroad tunnel transports. you name it. if it is made in america, it is not a hazardous or explosive

material. river was thehort busiest freshwater shipping in the world. our train tunnel -- things are transported through the entire world. they show us a freighter map. everywhere michigan products have made it around the world. isrt of antarctica, there not a consonant we do not touch. the investor bridge was completed november 15, 1929. when it is open, it is the longest extension bridge in the world. it holds that record for just -- when the ambassador bridge is completed, what it is known for is height. it allows shipments to travel as opposed to a drawbridge which every time itffic had to open or close. -- he builds the

bridge as an economic driver. it is a toll bridge. today it is still owned by an individual, mattie marin -- maroon. isoss the ambassador bridge nearly 10,000 cars a day. the main transports for semi trucks, leaving america and going through michigan, we see everything on those trucks from gerber baby food through serial --e through michigan anything and everything that has to be traded. the two biggest international trading partners in the world. in 1929, when the detroit windsor bridge opens and again in 1930 when the tunnel opens, they are still engineering's

marvel. not only architecturally but through prosperity. being able to bring our cigar manufacturing, bringing in the raw steel, there is also funny parts. when the bridge opened in 1930, it quickly gets the name of the detroit tunnel because it is being smuggled through it. for detroit, it is not only a theseut we have to have methods of transport or we would fairy --going close to ferries. holding products in detroit for as much as a year and causing freights in the value of products like grains. opening transit

countries is monumental to the city of detroit. opening through the great lakes in the eastern seaboard, it becomes a transit hub for the entire country. during world war ii, it is -- democracy, building and shipping out the allies forces. it would become a hub of we could nottoday be without access to the shipping channels, but up to the prosperity of the region. when you -- legalities of the international border crossing, whatever it is, it is with concerns and especially national security. when the bridge opens, in the

the and 40's, hundreds of ambassador bridge. post 9/11, security has meant that is all closed off. it has also meant that we also have to be where of legal trafficking -- aware of legal trafficking. we also have coast guard stations. across.traffic coming multiple agencies includes the dnr. michigan state police and detroit police had to work to

make sure what is traveling across the river and into our -- for the nearly 100 years, the ambassador bridge coupled with the train tunnel .nd the civilian tunnel as detroit continues to grow, it will be called the international bridge crossing. as we traveled through the next hundred years, production and manufacturing and coupled with that is out of the city. use the largest man in the world. the river is not long enough.

one day we are going to create more innovation. >> our staff recently traveled to detroit michigan to learn about its history. visit c-span.org/cities tour. you are watching american .istory tv >> live at gettysburg college in pennsylvania for the annual summer conference, first an announcement. the civil war institute on civil war experiences. in thehat take place atrium, which is part of the main dining hall. you will enter at a different location you have been doing for

the past couple meals. if you are participating in a dine in discussion across the street, continue walking straight into the glass portion of the dining hall. you will see a sign standing out in front of it. that is just for people for a dine in discussion. there are going to be tense set up with the name of the dimon -- alsotor and we often have someone checking you intimately have everyone we should have for the discussion. if you are not participating in the discussion come you can still eat in the main portion of the dining hall. enter the way you usually have been entering at the college conference.

opening for tomorrow stores. -- tours. if you need to drop off a tour for tonight, let us know. a you are looking to get on different tour, we can no longer accommodate those changes. are pretty much set for tonight. and i think we are ready to get started as long as we are good with c-span. all right. it is my honor and pleasure to introduce somebody who at this point probably needs very little introduction to most of you. peter carmichael is the director of the civil war institute. whereprofessor of civil -- war studies at gettysburg ll