The Gherkin is a level 4 unique building in Cities: Skylines, modeled after the real-world London building bearing the nickname.
To unlock it, you must:
- Have access to outside connections for ships
- Reach the Capital City milestone*
- Construct 2 harbors (passenger)
- Build 2 cargo harbors
*Although the Landmarks tab of the Unique Buildings menu is unlocked as early as the Worthy Village milestone, you’ll need to get to Capital City to unlock the harbors.
Once you’ve built the 2 harbors and 2 cargo harbors, you’ll be able to build the Gherkin from the Landmarks tab of the Unique Buildings menu.
As of game version 1.15, the Gherkin is the most expensive unique building at 600,000. You’ll also need to spend 280,000 in total for building the harbors.
By default, the Gherkin is only available on European-themed maps. However, you can make it (and other European buildings) available on all maps by enabling the European Vanilla Style.
Having Access to Ship Outside Connections
In order to build either the passenger or cargo harbor, you’ll need an outside connection for ships. There are maps that do not have an outside ship connection at all.
Among the official (non-workshop) maps, the following do not have the ship connection:
- Two Rivers
- Northwood Hills
- Wolf Creek
- Marble Canyon
- Biomes Valley
- Farmland Flats
- River Valley Plain
- Desert Pass
- Prussian Peaks
- Pine Rivers
- Crater Falls
- Desert Oasis
Generally the ship connection is out in the open sea, although there are some maps where they can be accessed from the rivers.
Make sure to plan your tile expansions to have access to the coastline.
Building the Harbors
Both the passenger harbor (only called ‘Harbor’ in-game) and cargo harbor can be found in the Ship tab of the Transport menu.
Both of these need to be built on coastlines.
As you try to place either along the coast, it will try to find a direct line to the outside ship connection.
If the line is obstructed by land, you’ll get an error message and won’t be able to place the harbor.
Each harbor comes with a segment of road built in, which you’ll need to connect to your road network.
Don’t forget that you’ll need to build two of each in order to unlock the Gherkin.
Using Your New Harbors
Unlike local modes of transport, you won’t need to set up lines for your passenger or cargo harbors in order to use them. They just need to be hooked up to your road network, power grid, and water lines and they’re good to go.
Be aware, though, that both these harbors can bring in a lot of traffic.
- Passenger harbors bring in tourists in large numbers.
- Meanwhile, you can expect the cargo harbor to be busy with delivery vans and trucks going in and out to serve your commercial and industrial zones.
For the passenger harbors, make sure you provide local transport options (such as a metro/monorail station, or bus or tram stop) close by to prevent tourists from whipping out their “pocket cars” to drive around your city.
As for the cargo harbors, try to provide them with direct access to and from your industrial areas (without needing to pass by your other zones), so the cargo trucks don’t clog up your local traffic.