"Welcome to West Oakland" is an iconic sign by GATS on top of a building at Martin Luther King, Jr. Way and 25th Street in Hoover Foster/Ghosttown. The sign has been there since at least 2009.
The front and 25th street side of the building was painted with the "Ants" mural by Daz, Desi W.O.M.E, Dave K of Community Rejuvenation Project.
Here is a picture of the building with a different mural on the right side (2011). This is a picture of the side that doesn't face the street (2010). The amazing Jessica Hess has painted this building.
This is what the building looked like before the mural (2009).