Sadly, many of Perth's grandest old buildings have been demolished over the years. Some of them remain, but they're usually quite isolated, being separated by many structures that have been created within the last fifty years or so. This is in contrast to Fremantle, which has done a better job of preserving its architectural past. 

In the CBD there are some sections where clusters of such buildings remain, however. One of these is Howard St, off St George's Terrace.