To find the observatory globe for the Global Impact achievement, head to the Volk area. Look at your map and at the top of the Volk area you will see two bridges. Stand between these bridges, but do not cross them. When you get to the bridges, look at your map again to notice a large mound of rocks behind you. Jump over them and you will be at the City Memorial Observatory. In the middle of the car park is a globe with metal bars around it. Get rid of the bars and pick up the globe, then unlock your achievement by going up to a gang member and throwing it at him. Note: Make sure the globe does not go in water as it sinks and you will have to get it again.
Just north of the Volk Boss "Gryzunova" is a building with a large world globe. Use this globe to kill fifteen gang members and earn the achievement.