Despite the continuous efforts of governments and universities to avoid the underrepresentation of women entering engineering degrees, the trend has not reverted, and this is a general fact all over the world. This fact goes against the tendency of a growing ratio of women in tertiary education, so causes must be investigated. This research examines two main questions: Is it possible to break the invisible barriers that prevent girls from entering in engineering degrees by means of an engineering project or activity? And are there important misconceptions about the role of women in engineering professions and about engineering itself among high school girls? An extensive survey has been carried out between three groups of students: students of the last years of high school (834), students of the first year of engineering degrees (319), and students of the first year of sciences degrees (209). A set of visits to the high schools was developed and a contest of engineering projects was carried out too. The results show that there are important misconceptions in the knowledge that high school students have about engineering degrees and engineering. The visits and the project contest had a good impact that encouraged girls to take engineering activities in their curricula. The main finding is that even though girls see engineering professions as very well valued, they are convinced that engineering is not a profession for women, which suggests that there are educational barriers acquired during earlier stages of their lives.