My new iMac's 1 Terabyte storage is full of Applications?

My new iMac desktop is less than a month old, and I didn't transfer much over to it (about 50 gigs of stuff at most). But now when I look in storage, 887 gigs of space is taken up by Apps. I didn't really download anything new (Microsoft Office, but there's no way that takes up so much space). Any ideas about what is happening to my computer? Thank you in advance!