Rhineland

Nigra gate is the largest Roman edifice on German soil. The gateway (late 2C) was designed for military use to defend the northern ramparts. — Michelin Guide

This enormous 4th-century bathing palace once housed cold- and hot-water baths and a sports field. — Fodor's

The palatial 1705 Kurfürstliche Residenz was once the immodest home of the prince-electors of Cologne and has been part of Bonn’s university since 1818. — Lonely Planet

The palace contains one of the most famous achievements of rococo architecture, a staircase by Balthasar Neumann. — Fodor's

Mainz's Gutenberg Museum is worth the 5 Euro entrance fee. — Afar Magazine

Dominating the skyline of Mainz and commanding center stag of the Altstadt, is the Mainzer Dom, also known as the Cathedral of St. Martin. — Afar Magazine

The birthplace of Karl Marx has been transformed into a museum. — Michelin Guide

One of the Rhineland's main attractions lies 4 km (2½ miles) south of St. Goarshausen: the steep (430-foot-high) slate cliff named after the beautiful blonde nymph Loreley. — Fodor's

Within its massive walls are a collection of weapons and manuscripts, a medieval botanical garden, and a self-service restaurant. Try to get a table on the terrace to enjoy the stunning view. — Fodor's

The noise of the city fades to a quiet hum on the viewing platform located at a lofty 103m atop the KölnTriangle office tower on the right Rhine bank across from the Cologne Cathedral. — Lonely Planet

This pointed bit of land, jutting into the river like the prow of an early ironclad warship, is at the sharp intersection of the Rhine and Mosel rivers. — Fodor's

This vast castle was reconstructed in 1842 in the neo-Gothic style and based on that of English manor houses. — Michelin Guide

The main market square of Old Trier—lined with gabled houses from several ages—is easily reached via Simeonstrasse. — Fodor's

This small applied arts museum re-creates the living spaces and lives of 17th- and 18th-century patricians. — Lonely Planet

If you're a steam-lover, try this high-tech spa with a venerable history. — Fodor's