v2.21 is being voted on
If it passes, the chain stops at that block until validators holding two thirds of the stake restart on v2.21. That usually takes minutes. Nothing is lost: transactions just wait until blocks resume. The time is estimated from the average block time, so it drifts a little as the day goes.
Validators missing blocks
Blocks each active validator did not sign in the signing window, and how close that is to being jailed.
Bridges
Terra reaches other chains over IBC. Relayers carry each packet across and keep both sides’ light clients up to date. When nobody relays, transfers wait; a light client left alone past its trusting period stops the bridge until it is renewed.
Reading every channel takes a little while the first time.
Public endpoints
Wallets and apps reach Terra through these. The list is the Cosmos chain registry’s, which wallets read, plus a few endpoints apps use that it does not list. This site’s server asks each one for the latest block every minute.
Openfields apps
Checked every ten minutes from GitHub’s machines, outside the servers that run them: the page loads and its data answers with live data. This month so far.
The validator set
Blocks need validators holding more than two thirds of the stake to be online and signing. These numbers say how few it would take to stop that.
The last seven days
Every ten minutes a check on GitHub’s machines, outside this site’s servers, reads the chain and every endpoint and writes one line to a public log. This is that log.