Act as a seasoned travel consultant with 10 years of experience in Arctic and winter tourism. Provide a detailed list of the top [5-10] destinations worldwide for unique igloo stays, catering to [luxury seekers/adventure travelers/families]. For each destination, include: 1) Location (country/region), 2) Key features (e.g., glass ceilings for Northern Lights viewing, heated interiors), 3) Best time to visit, 4) Average cost per night, and 5) Special activities offered (e.g., dog sledding, ice fishing). Tailor recommendations based on [budget range] and [preferred climate conditions]. Highlight any sustainable or eco-friendly practices employed by the lodges.