21 beautiful old buildings that no longer exist

The world's skylines are constantly changing.

Some of the most historically stunning architectural gems are now gone forever, thanks to new constructions, natural disasters, and political conflicts.

While some were rebuilt or changed location, others are now only memories of the past.

We've put together a collection of breathtaking buildings that were once marveled at for their design and role in society.

Click through to see some of the most iconic hotels, businesses, theaters, and private homes.