This altar and pillar have been interpreted by many to refer to the great pyramid. This pyramid is, indeed, a remarkable structure, exhibiting a high degree of technical knowledge. However, the pyramid was already old in Isaiah's day, and the prophecy indicates that the fulfillment was to be far in the future, probably referring to a structure not yet built.

Source:

KJV Defenders Study Bible, by Dr. Henry Morris, Ph.D.
Publisher: Thomas Nelson
Language: English
DEF 10 ISBN 0-529-10444-x
DEF 10-1 ISBN 0-529-10445-8