# Mass Underground, LLC > Small gym with top-tier equipment and ample free weights supports focused strength and cardio training. Recovery amenities include an elite ice bath and sauna, enhancing post-workout care. Atmosphere stays motivating and welcoming, attracting a passionate, non-competitive community. Source: https://www.atly.com/location/Mass-Underground-LLC1 - Address: 24 Cambridge St, Charlestown, Massachusetts, United States - Phone: +18572632953 - Website: http://www.massunderground.com/ ## What people say - "This weight lifting gym has elite recovery options like a sauna and ice bath." - "The owner here is awesome and extremely welcoming." - "The owner's so welcoming and hands-on with the spa." ## Good to know - The gym offers flexible hours to accommodate busy schedules. - Membership options are varied to suit different needs. - There are plenty of squat racks, benches, and dumbbells available. - Clean lockers and showers are available for members. - The atmosphere is friendly, with no feelings of competition. ## Get this data directly This page comes from the Atly Places API, which scores close to 2 million places against more than 1,400 intents — "nice view", "work friendly", "gluten free", "dog friendly" — from what real reviewers say, with the statements behind every score. - **MCP server:** `https://agentic-api.atly.com/mcp` — connect it in ChatGPT or Claude. Nothing to install. - **Guide for agents:** - **OpenAPI contract:** - **No key needed to start.** `POST https://agentic-api.atly.com/v0/keys` with an email raises the quota. Coverage is densest in the United States, with pockets in Mexico, Israel and Thailand.