Pascal is an influential imperative and procedural programming language, designed in 1968–1969 and published in 1970 by Niklaus Wirth as a small and efficient language intended to encourage good programming practices using structured programming and data structuring.
However, Pascal today is a modern programming language. Its golden era is from the late 80's to the early of 2000's. Though today it's no longer widely used, Pascal compilers are still actively used and developed. The syntax is simple and easy, yet powerful. Pascal compilers are known as very very fast compilers that make C-like compilers look like a bunch of snails.
Pro Cross platform
Pro Enforces good programming practice
Numerous strong compile time checks with optional runtime checks ensure one doesn't do stupid things and even when one does (because the compiler can't prove it at compile time), the binary will check and report it at runtime.
Correct modular programming implementation with proper namespacing, no file inclusion hack.
Pro Easy GUI creation
Visual Basic may have predated Delphi but Delphi was the ground breaking visual designer which set the standards expected today by most gui developers
Its rich component set was well designed, structured and extensible, it even has the ability to display live data from the attached database in its Data controls
Pro Rich existing libraries
Both shipped with implementations and spread all over the web. Both natively written or bindings to libraries written in other languages. Typically to build non-trivial applications there's no need to surf the web as many things are implemented already. Streaming, output templating, socket & networking, web, database, image manipulation, high performance graphics, (de)compression, (de|en)cryption, regex, unit testing, json manipulation, google API, indexing, multithreading, external process management, the list just goes on and on!
Pro Language depth
Object Pascal is being used to write custom kernels (Ultibo) and operating-systems for various ARM boards. So the way you work with the code scales from low-level to pure OOP high-level. Object Pascal has the same level of depth that you find in C/C++ but with added productivity.
Con No language standard
After the Wirth era, practically there is no official Pascal language standard. Delphi used to be the dé facto standard especially for industry, but today Free Pascal is starting to get better support. However, there are some other Pascal language variants such as Smart Pascal, Oxygene (from RemObjects), Pascal ABC, etc. that each has its own styles.