Powell's is, for me, one of the three must-visit places in Portland. The other two are Jake's and the Japanese Garden.
Powell's is probably not the biggest bookstore in the world, but it has to be the best. Its main storethere are severaloccupies an entire city block and is 3 stories tall. It carries both new and used books. It has a separate technical bookstore down the street. Carrying new and used books on the same shelf is thought to be the secret to Powell's tremendous success.
From there you can go down to Powell's Technical Bookstore.
Here is what Powell's looks like from the outside:
Here is what the Technical Bookstore looks like:
Here is what a part of one of the bookrooms in Powell's looks like: