Sidewalk chalk is a no-brainer for a fun time for kids. Not only does it let kids create big, bold art, but it also lets them do something every kid likes: draw on stuff they normally shouldn't.

Can you chip in? As an independent nonprofit, the Internet Archive is fighting for universal access to quality information. We build and maintain all our own systems, but we don’t charge for access, ...

Abstract: This standard establishes a set of performance and functional requirements necessary for enhancing performance, availability, operations, and train protection using a CBTC system. Scope: ...