In 1845, Pfeiffer set out to Scandinavia and Iceland. In preparation for her travel, she studied English and Danish as well as how to preserve natural specimens and take daguerreotypes. The adventure began on 10 April 1845. She traveled from Vienna to Copenhagen, then boarded the "Johann" on 4 May, reaching Hafnarfjörður on the southwest coast of Iceland in eleven days. She rode to Reykjavík on horseback and toured the geothermal area of Krýsuvík. She proceeded to visit the Golden Falls and climb the volcano Mount Hekla. After her return to Denmark, she took a small steamer north to Gothenburg, Sweden and from there, went further north to Norway.