This is the palace where Alexander the Great was made king more than 2,300 years ago

It was the largest building of classical Greece: the palace where Alexander the Great was proclaimed king before he launched a conquest that took him as far as modern-day Afghanistan.

The Palace of Aigai in northern Greece was fully reopened Friday following a 16-year renovation that cost more than 20 million euros and included financial support from the European Union.

It was built more than 2,300 years ago during the reign of Alexander's father, Phillip II, who had transformed the kingdom of Macedonia into a dominant military power of ancient Greece. Aigai was its royal capital.

"After many years of painstaking work, we can reveal the palace … What we are doing today is an event of global importance," Prime Minister Kyriakos Mitsotakis said at an inauguration event at the site Friday.

The palace contained column-rimmed courtyards, courts, places of...