In the Mass Effect universe, the homeworlds of each major race are politically important locations, and that includes the Salarian homeworld of Sur'Kesh.
Not just anyone may be invited to the Salarian homeworld, since this is a place of secrets and complex rules. Although Sur'Kesh doesn't have the blistering heat of Tuchanka or the intense solar radiation of Palaven, it is still a deadly and well-defended place. Nearly all Salarian Union interests can be traced back to this planet.
Life on Sur'Kesh
This planet is largely covered in oceans and temperate jungles; before Salarian industrialization, it was a wild and untamed place. It may not be quite as vicious as Tuchanka, but Sur'Kesh is still hazardous to unprepared visitors, as its jungles are home to hazardous flora and fauna alike. Getting lost is a major concern. Fortunately, the Salarians are as well-developed as the Asari and Turians, and they have built many cities and STG (Special Tasks Group) across the planet. This makes it possible to visit Sur'Kesh and never step foot in the deadly jungle.
The Salarians are quite liberal with their ideas of cybernetics, technological research and innovative ideas, contrasting with the slow and deliberate ways of the Asari High Command and Turian Hierarchy. But unlike the Drell, who overpopulated their world and faced a famine, the Salarians used their sharp intellect to engineer a perfect balance between machine and nature. Today, Sur'Kesh is home to a massive population of around 11 billion Salarians, but it is not overpopulated. Instead, the Salarians have developed and now follow strict and complex breeding rules, which are based on inter-family politics. Salarians do not have concepts of marriage and romantic love like other races, so it's easier to keep the huge population in balance.
Furthermore, the Salarians are master engineers able to process huge amounts of fresh water in their cities for use without putting undue strain on Sur'Kesh's ecosystem. Vast swaths of the jungle are still present to maintain that ecosystem, and well-lit, clearly defined pathways allow Salarians to travel from one city or town to another safely.
Sur'Kesh in the Game
Commander Shepard visits several homeworlds during the events of Mass Effect 3, and excuding Earth, Sur'Kesh is the first homeworld visited. As for why, Urdnot Wrex needs a genophage cure in exchange for lending Krogan aid to the Turians, which means evacuating fertile female Krogan from Sur'Kesh. Shepard, Wrex and another squadmate of choice visit the world and land on a typical STG base, a place of mad science, armed soldiers and incredible secrets.
If Captain Kirrahe survived Mass Effect, he returns as Major Kirrahe, and he explains that the STG is always expecting trouble, thus the tight security. Shepard and Wrex meet up with Mordin Solus and prepare to evacuate the last fertile Krogan female. However, Cerberus comes knocking, and their troops and shuttles are all over the STG base before long. Wrex keeps some of them busy while Shepard and Mordin escort the Krogan to the evacuation point.
The battle reaches its climax when an Atlas-class combat mech is dropped onto the Sur'Kesh base and confronts Shepard. Shepard and Wrex manage to turn the battle around and evacuate the Krogan, and Sur'Kesh is left far behnd. Shepard notes that, although the Salarian homeworld is currently far away from the Reapers, the Salarians will definitely get dragged into the war sooner than later, and they must get ready. Otherwise, Sur'Kesh's sprawling jungles will soon be ablaze.