A passenger ship arriving at a harbor.
Each city needs to be connected to the outside world. The main reason for this is to allow industry to work with full efficiency, but also tourists use outside connections to travel to the city. There are many possibilities on how to get the best of your connections, so read on to find out more about importing and exporting goods, boosting your city attractiveness with monuments and luring in tourists to spend their hard-earned money in your commercial districts.
Tourism
Others using the outside connections are tourists. They come in through many transportation types, but when you start a game, they use the highway only. Tourists come to your city always, but their numbers are decided by how attractive your city is. Attractiveness is raised by high land value and having monuments. Land value can be increased by building parks and plazas, which also help zoned buildings in the city to level up. Monuments are quite exciting! They are buildings, parks, plazas and statues that you can earn through actions in the game. For example, when your city has produced 1 000 units of goods, you gain the Stadium of Many Things. Upon reaching the goal, the Stadium becomes available in the menu and you can place it in your city. It's a popular location for many of your citizens, but also draws in tourists and increases happiness of citizens living near it. It's often a good idea to make sure monuments have good public transport connections, so roads around them don't get too busy.
Tourists arrive at the terminal.
Tourists come to your city to see sights and shop. This can greatly increase your tax income, because tax is paid for every unit of goods sold. It also means that tourists want to get to your commercial areas. Tourists can come to the city by ship, airplane, train or with their own car. Especially for tourists that come in with other means than their own car, public transport is very important. The better tourists can get around, the more they tend to spend money in your city. The key is to earn and build monuments to draw in tourists, and then provide them with good transportation option inside the city to keep them there. Large amounts of tourists can also create traffic jams if they use their own cars instead of public transport, so you can avoid a lot of problems by giving them the means to move around easily.
Monuments
While monuments provide the city with happiness and attractiveness boost, there's more! Monuments are grouped into five "skill trees", pathways to gaining the ultimate buildings: Wonders. Different monuments are suited for different playing styles, so you can pick your favourite, play in that style and eventually gain the coveted Wonder. Wonders are massive buildings that basically remove one need from the city, but more on those in another development diary!
The Expo Center makes people living nearby very happy.
Import and export
The most optimal city that gives out biggest amount of taxes possible, would produce and use up everything inside the city. But since it takes time to get there and most cities can benefit from outside help, there are possibilities to import and export goods and natural resources. All industry buildings need a small amount of natural resources to produce goods, that are then sold in commercial areas. Natural resources can be produced in your city, but only specialized industry can provide them, and it doesn't unlock until a bit further in the game. So, to get your industry up and going, you need to be connected to a highway. This also works for power plants that use a specific resource to work, for example the oil power plant. It prefers resources inside the city, so if you have oil industry set up, it will order oil from local suppliers. If not, a load will arrive from outside the city. While the most tax income is gained by having your own industry provide everything, it might be better to not have polluting oil industry and rather have the oil be brought from other cities. It's your choice!
Cargo arrives and leaves on a cargo ship.
Maps have many highway connections available, but the starting tile always offers at least one. Some starting tiles have the highway running through them, other only have a small ramp that you can connect to. If the highway comes into the way of your growing city, you don't have to keep it as it is. Re-building it as elevated lets you add ramps in the places you need and have inner city traffic pass under the highway. You can also just connect the ends of a high way to your city and let the traffic find its own way. There are almost endless possibilities! Keep an eye on where your industrial areas lie, because they will get most of the traffic, so a ramp near the industrial area is always a good idea.
Exporting goods works best via cargo train stations and cargo harbors. Before these are available, industry will ship excess goods to other cities with trucks, which puts a strain on the roads. With a harbor or a train connection, you can have the trucks only operate between the industry buildings and the harbor/station, and easily control where the large trucks drive. Commercial buildings inside the city are a priority, they will order goods to sell and industry always first ships to them, but if their stockpiles are full, goods can be sold to other cities.
Karoliina Korppoo,
Lead designer on Cities: Skylines
PS. UI has been re-done, how do you feel about it? We are very proud!
Trains can also carry cargo.
A close-up on the Expo Center.
It is the way to go 
