Under Review is an availability status for Roblox places. A place is typically put under review by moderators if it is found to be in violation of the Terms of Service. Some examples of a place breaking the Terms of Service include having inappropriate features, not having a text filter, copyright issues, having stolen content, being a stolen copy of an existing place, or being a scam. The scams are usually "free Robux" scams and "Bait and Switch" scams.
Players may receive moderation action for their games being put under review, particularly if it is determined that the game violates Roblox's Terms of Service. Often, if the creators remove or otherwise fix terms-breaking elements in their places, the place will have it's Under Review status revoked. For example, if one place did not have a text filter and was put under review, but the creator has since then added filtering and has contacted Roblox, the place will be made playable again. If the place has no rule-abiding reason to exist, then it is content deleted.
If the servers haven't shut down yet, players can still play the place by joining an active server on the server list.
Some notable places that were put/are under review include Admin's Starting Place, Call of Robloxia 5, Ro-Bio & Ro-Bio 2 (now permanently deleted), Vehicle Simulator, Town of ROBLOXia, Boys and Girls Hangout, Pokémon Brick Bronze (now permanently deleted), EMPIRE Theatre V9, Pilgrim Islands Reborn, Dragon Ball RP: Legends, Work at a Pizza Place, Roblox High School, The Neighborhood of Robloxia, Unicorn Adventure Obby, Mount Everest Climbing Roleplay, Islands, Puppet, and Welcome to ROBLOX Building, a game created by the official ROBLOX account.