The first error addresses my failure to declare the language of my page. Simple fix.
The second error appears twice (also Error 4) claims that I forgot to follow the slash with a bracket. But, really, I input a slash instead of a bracket because I didn't know what I was doing. Another easy fix.
I'm not sure why it comes up twice, because it's referring to the exact same thing.
The third error is related to the previous one--the missing bracket is still throwing things off here.
With the fifth error, I'm pretty sure the missing bracket is still the problem.
Yup. The next two errors also point back to the missing bracket.
Ah, something new! In the eighth error (also the eightieth error; cool, right?), I included a non-existing end tag because I didn't know that "br" is an empty tag.
The next error occured exactly 60 times (errors 9-19, 24-66, and 72-77): I didn't terminate the character reference (non-breaking space) with a semi-colon. I fixed this by finding and replacing all instances of the character reference with the correct form (using Atom, which is awesome!).
Error 20 appears 5 times (also errors 22, 67, 69, and 78): I used the align attribute on the caption element, which is not supported in HTML5. I removed this from the HTML and styled it properly in the style sheet.
In Error 21, which appears 6 times (also errors 23, 68, 70, 71, and 79), I didn't provide a text alternative, so I added them in the revised HTML.
I ran the HTML through the validator again to make sure I corrected everythiing. All fixed!
The CSS validation, much unlike the HTML validation, resulted in a single error (see below): I input a property ("align") that doesn't exist. Funnily enough, I never included the image that I was attempting center in the HTML, so I never had to correct that error to properly style my page. I also didn't remove that element selector.
And that was it! Not too bad, not too bad...