Natural history museums are great places for learning new concepts and enhancing social skills and motivation. However, it is often difficult for teachers to make full use of the museum as a learning environment. Some teachers seem to be more successful than others in crossing the boundaries--they enjoy and value field trips and advocate for them in the teaching community. Such teachers are a valuable source of information on how to overcome factors that hinder field trips and support meaning-making in the museum. This study explored the practices of eight Estonian elementary school teachers who create, conduct, and analyse learning activities at a natural history museum without the direct help of museum educators. All participants frequently and willingly teach across different learning environments. A qualitative multiple case study strategy was used. The teachers were interviewed and learning activities were observed. Field notes, interview transcripts, lesson plans, and thick descriptions of observations were analysed. The participating teachers valued learning across different learning environments and were skilful in overcoming most problems connected to field trips. Teachers demonstrated supportive relationships with their students, which seemed pivotal in facilitating engagement. Estonian elementary teachers seem to have more autonomy in their teaching practices compared with their colleagues from other countries. However, participants struggled to use hands-on and interactive exhibits. This study highlighted the need for more collaboration between museum educators and Estonian elementary school teachers, especially in order to create more individualized and problem-solving oriented learning tasks.