This is up on my classroom wall printed as 4′ x 16′, printed at 130 DPI. The actual file weighs in at 16.9MB in high quality jpeg format; 29,000 x 3,000 pixels.
Click here for the 300 x 3108 preview, click here for the full-size version. Free for you to use, share & modify however you like. If you’d like a large-scale printed version, we can print them using our uber printer at my school. Tweet me if you’d like one; we can print them for around £45… I’ll get a firmer idea of cost if anyone’s interested.