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                                                                     EXHIBIT 8.3


                                                              September 22, 2000


                       Amended and Restated Agreement and
                             Plan of Reorganization
                         Dated as of September 20, 2000
                    Among Terra Networks, S.A., Lycos, Inc.
                            and Lycos Virginia, Inc.

Dear Sirs:

     We have acted as counsel for Lycos, Inc., a Delaware corporation ("Lycos"),
in connection with the merger of Lycos with and into a wholly owned subsidiary
of Lycos incorporated in Virginia ("Lycos Virginia"), with Lycos Virginia
surviving such merger (the "Reincorporation Merger") and the immediately
following statutory share exchange pursuant to the Virginia Stock Corporation
Act such that Lycos Virginia will become a wholly owned subsidiary of Terra
Networks, S.A., a company organized under the laws of the Kingdom of Spain
("Terra") (the "Share Exchange" and, together with the Reincorporation Merger,
the "Reorganization") pursuant to an Amended and Restated Agreement and Plan of
Reorganization, dated as of September 20, 2000, among Terra, Lycos and Lycos
Virginia (the "Reorganization Agreement").


     In that connection, you have requested our opinion regarding certain U.S.
Federal income tax consequences of the Reorganization. In providing our opinion,
we have examined the Reorganization Agreement, the registration statement on the
Form F-4 (the "Registration Statement"), which includes the proxy statement of
Lycos and prospectus of Terra (the "Proxy Statement/Prospectus"), filed with the
Securities and Exchange Commission (the "SEC") on September 22, 2000, the
letters delivered to us by each of Terra and Lycos for purposes of this opinion
(the "Representation Letters"), and such other documents and corporate records
as we have deemed necessary or appropriate for purposes of our opinion. In our
examination of such documents and in our reliance upon them in issuing this
opinion, we have assumed, with your consent, that all the documents submitted to
us as photocopies or by telecopy faithfully reproduce the originals thereof;
that the originals are authentic; that all such documents submitted to us have
been or will be duly executed and validly signed (or filed, where applicable) to
the extent required in substantially the same form as they have been provided to
us; and that each executed document will constitute the legal, valid, binding
and enforceable agreement of the signatory parties. In addition, we have assumed
that (i) the Reorganization will be consummated in accordance with the
provisions of the Reorganization Agreement and the Registration Statement, (ii)
the statements concerning the Reorganization set forth in the Reorganization
Agreement and the Registration Statement are and will remain true, complete and
correct, (iii) the representations made by Terra and Lycos in their respective
Representation Letters are true, complete and correct and will remain true,
complete and correct at all times up to and including the Closing (as defined in
the Reorganization Agreement), (iv) that all obligations imposed on or
convenants agreed to by the parties pursuant to any of the documents have been
or will be performed or satisfied in accordance with their terms in all material
respects and (v) any representations made in the Representation Letters "to the
knowledge of" or similarly qualified are correct without such qualification. If
any of the above described assumptions are untrue for any reason or if the
Reorganization is consummated in a manner that is different from the manner in
which it is described in the Reorganization Agreement or the Proxy
Statement/Prospectus, our opinions as expressed below may be adversely affected
and may not be relied upon.


     Based upon the foregoing, for U.S. Federal income tax purposes, (i) each of
the Reincorporation Merger and the Share Exchange will constitute a
reorganization within the meaning of Section 368(a) of the Internal Revenue Code
of 1986, as amended (the "Code"), (ii) Lycos and Lycos Virginia will each be a
party to the reorganization within the meaning of Section 368(b) of the Code
with respect to the Reincorporation Merger and Lycos Virginia and Terra will
each be a party
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to the reorganization within the meaning of Section 368(b) of he Code with
respect to the Share Exchange, (iii) no gain or loss will be recognized by Lycos
or Lycos Virginia as a result of the Reincorporation Merger or by Lycos Virginia
as a result of the Share Exchange, (iv) no gain or loss will be recognized by
shareholders of Lycos who exchange all of their Lycos common stock solely for
shares of Lycos Virginia common stock pursuant to the Reincorporation Merger and
(v) no gain or loss will be recognized by shareholders of Lycos Virginia who
exchange all of their Lycos Virginia common stock for Terra stock pursuant to
the Share Exchange except with respect to cash received in lieu of a fractional
share interest in Terra stock and except in the case of any shareholder of Lycos
or Lycos Virginia that is a U.S. person and a "five percent transferee
shareholder" as defined in Treas. Reg. Section 1.367(a)-3(c)(5)(ii) that has not
entered into a five-year gain recognition agreement in the form provided in
Treas. Reg. Section 1.367(a)-8.

     Our opinions are based on current provisions of the Code, Treasury
Regulations promulgated thereunder, published pronouncements of the Internal
Revenue Service and case law, any of which may be changed at any time with
retroactive effect. Any change in applicable laws or the facts and circumstances
surrounding the Merger, or any inaccuracy in the statements, facts, assumptions
or representations upon which we have relied, may affect the continuing validity
of our opinions as set forth herein. We assume no responsibility to inform you
of any such change or inaccuracy that may occur or come to our attention. In
addition, our opinions are limited to the tax matters specifically covered
hereby, and we have not been asked to address, nor have we addressed, any other
tax consequences of the Reorganization.

     This opinion is being provided solely for the benefit of Lycos. No other
person or party shall be entitled to rely upon this opinion.

     We consent to the filing of this opinion as an exhibit to the Registration
Statement and to the reference to Cravath, Swaine & Moore in the Registration
Statement under the caption "Material U.S. Federal Income Tax Considerations".
In furnishing such consent, we do not concede that we are within the category of
persons whose consent is required under Section 7 of the Securities Act of 1933,
as amended, or the rules or regulations of the Securities and Exchange
Commission promulgated thereunder.

                                          Very truly yours,

                                          CRAVATH, SWAINE & MOORE

Lycos, Inc.
400-2 Totten Pond Road
Waltham, MA 02154