We give a concise presentation of the Univalent Foundations of mathematics outlining the main ideas, followed by a discussion of the UniMath library of formalized mathematics implementing the ideas of the Univalent Foundations (section 1), and the challenges one faces in attempting to design a large-scale library of formalized mathematics (section 2). This leads us to a general discussion about the links between architecture and mathematics where a meeting of minds is revealed between architects and mathematicians (section 3).The main characters in Martin-Löf type theory (MLTT for short) are types and elements of these types. If T is a type, then the expression t : T denotes that t is an element of T . In particular, if T is a type and t, t ′ are elements of T there is a new type called the identity type of t and t ′ denoted t = T t ′ . Sometimes for convenience we will omit the type information and we will simply write t = t ′ . When one considers only a single element t, i.e. t ′ is definitionaly equal to t, the identity type t = T t has always at least one element denoted idpath t, i.e. the expression idpath t : t = T t is well-formed. This term idpath is called a constructor and the identity types belong to a particular class of types called inductive types. Indeed, besides their constructors (an inductive type can have either a single constructor or many constructors), a family of types defined inductively (like the identity types are when introduced formally) obey an induction principle. In the case of identity types, this induction principle states that given a type T , an element t : T , a family F of types indexed by an element t 0 : T and an element p 0 : t = T t 0 , if there is an element f : F t (idpath t) (the family F instantiated with the terms t and idpath t), then for any elements t ′ : T , p : t = T t ′ there is an element of the type F t ′ p, and moreover this element is f itself when t ′ and p are definitionaly equal to t and idpath t, respectively. Of course, one can iterate the process of building identity types, namely given p and q two elements of the identity type t = T t ′ , one can form the identity type p = t= T t ′ q and so on. As it happens, these identity types lead to a very rich mathematical structure and there is a surprising connection between homotopy theory and MLTT (the latter being also coined Martin-Löf dependent type theory in reference to these dependent types, i.e. dependent on previous types for their definition which may be inductive, like in the case of identity types, or not). Roughly, one can think of T as a space, two elements t and t ′ of T as points of this space, two elements p and q of the type t = T t ′ as paths from t to t ′ in the space T , and the elements of p = t= T t ′ q as homotopies between the paths p and q and so on (the elements of the successive iterated identity types being higher homotopies). Under this correspondence idpath t is the identity path between a point t and itself in the given space. Each type bearing the structure of a weak ∞-groupoi...