The unexpected and enduring success of the original SimCity, combined with the relative lack of success with other "Sim" titles, finally motivated the development of a sequel. SimCity 2000 was a major extension of the concept. It had a near-isometric dimetric view (similar to the earlier Maxis-published A-Train)[10] instead of overhead, land could have different elevations, and underground layers were introduced for water pipes, subways and road tunnels.