A Lemming Holiday is the second or third level, depending on version, in Xmas Lemmings 1992.
Strategy[]
Make the first Lemming a Digger a few steps after landing. The second will escape the pit, so have it build a couple tiles at the edge to get over the gap then bash or mine to cut it short. Build again to seal that gap then have the Digger mine or bash. Make a right-facing Athlete to serve as a Trailblazer. Bash through the ice pillar then build from the second snow mound up to the top of the icicles. Use as many Builders as needed to turn around and ensure a perfect seal. Bash through the icicles, and the tunnel landing should be just at the bottom of the rocks. Around a third of the way up, build to turn around then back towards the icicles to make a safe landing for the others. Bash through the snowman, then build over the last gap to the Exit portal. Finally, bash through the large snow wall to free the herd.