Construction on Disney California Adventure began in 1998. DISNEYLAND had to find new parking areas to use as the old one began its transformation into a new theme park.
The park began to take shape, with the Paradise Pier area getting finished first. The visible progress confused guests who began thinking the park was already open in early 2000.
Downtown Disney was also under construction. Below we see ESPN Zone and Rainforest Cafe under construction.
As things began to look finished, it might have seemed odd that there was still much dirt onsite. In a theme park, the last part of construction is to put down the pavement and concrete. This allows for changes to be made right up until the end. For example at California Adventure, two soundstages and the Tower of Terror were put on hold and didn't open up with the rest of the park. (One of the soundstages would open in November of 2001 and the Tower of Terror wouldn't open until 2004.)
As construction neared completion, Disney would soon be ready to unleash its newest theme park on the world.