The Bay addon - SimCity 4: Rush Hour

You don't just build your city; you breathe life into it. Sculpt mountains, dig riverbeds, and seed forests as you lay the groundwork for your creation. Then, use your god-like powers to construct the most realistic metropolis you can imagine. Whether you want to build mansions on mountainsides or cross canyons with bridges, the impact of your decisions is immediate. But while each click of the mouse can create, it has equal capacity to destroy. Capping an erupting volcano might save your city, or it might reroute lava down busy city streets. Sending police to quell a riot might calm down the crowd, or it might spur even further anarchy. With every decision you make, your city and your Sims will respond – for better or for worse. It’s up to you to be their guide.