The HTML interface to your SPARQL endpoint is not your SPARQL endpoint

Remember what the 'P' in 'SPARQL' stands for.

Something that happens to me now and then: I’ll hear that an organization with a lot of interesting data (science, music, whatever) makes the data available on a SPARQL endpoint. I send my browser to the URL listed as the SPARQL endpoint and I see a web form. I enter a simple query on the web form to retrieve a few random triples, click the form’s button, and the results of my query appear. Then I enter fancier queries to explore the endpoint’s data.