Globular clusters  are composed of hundreds of thousands of very old stars, all tightly packed in a spherical area located near or in the halo of a galaxy.
M13 shown below is a great globular cluster easily visible in binoculars in the constellation of Hercules.

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An Open cluster is composed of hundreds of stars born in the same molecular cloud about the same time.
This is the Pleiads Open star cluster M45.  September, 2018
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M 22 Globular cluster